path: root/src/share/database/scripts/mysql/dhcpdb_create.mysql

# Copyright (C) 2012-2023 Internet Systems Consortium, Inc. ("ISC")
#
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

# This is the Kea schema specification for MySQL.
#
# The schema is reasonably portable (with the exception of the engine
# specification, which is MySQL-specific).  Minor changes might be needed for
# other databases.

# To create the schema, either type the command:
#
# mysql -u <user> -p <password> <database> < dhcpdb_create.mysql
#
# ... at the command prompt, or log in to the MySQL database and at the 'mysql>'
# prompt, issue the command:
#
# source dhcpdb_create.mysql
#
# This script is also called from kea-admin, see kea-admin db-init mysql
#
# Over time, Kea database schema will evolve. Each version is marked with
# major.minor version. This file is organized sequentially, i.e. database
# is initialized to 1.0, then upgraded to 2.0 etc. This may be somewhat
# sub-optimal, but it ensues consistency with upgrade scripts. (It is much
# easier to maintain init and upgrade scripts if they look the same).
# Since initialization is done only once, it's performance is not an issue.

# This line starts database initialization to 1.0.

# Holds the IPv4 leases.
CREATE TABLE lease4 (
    address INT UNSIGNED PRIMARY KEY NOT NULL,  # IPv4 address
    hwaddr VARBINARY(20),                       # Hardware address
    client_id VARBINARY(128),                   # Client ID
    valid_lifetime INT UNSIGNED,                # Length of the lease (seconds)
    expire TIMESTAMP,                           # Expiration time of the lease
    subnet_id INT UNSIGNED,                     # Subnet identification
    fqdn_fwd BOOL,                              # Has forward DNS update been performed by a server
    fqdn_rev BOOL,                              # Has reverse DNS update been performed by a server
    hostname VARCHAR(255)                       # The FQDN of the client
    ) ENGINE = INNODB;

# Create search indexes for lease4 table
# index by hwaddr and subnet_id
CREATE INDEX lease4_by_hwaddr_subnet_id ON lease4 (hwaddr, subnet_id);

# index by client_id and subnet_id
CREATE INDEX lease4_by_client_id_subnet_id ON lease4 (client_id, subnet_id);

# Holds the IPv6 leases.
# N.B. The use of a VARCHAR for the address is temporary for development:
# it will eventually be replaced by BINARY(16).
CREATE TABLE lease6 (
    address VARCHAR(39) PRIMARY KEY NOT NULL,   # IPv6 address
    duid VARBINARY(128),                        # DUID
    valid_lifetime INT UNSIGNED,                # Length of the lease (seconds)
    expire TIMESTAMP,                           # Expiration time of the lease
    subnet_id INT UNSIGNED,                     # Subnet identification
    pref_lifetime INT UNSIGNED,                 # Preferred lifetime
    lease_type TINYINT,                         # Lease type (see lease6_types
                                                #    table for possible values)
    iaid INT UNSIGNED,                          # See Section 12 of RFC 8415
    prefix_len TINYINT UNSIGNED,                # For IA_PD only
    fqdn_fwd BOOL,                              # Has forward DNS update been performed by a server
    fqdn_rev BOOL,                              # Has reverse DNS update been performed by a server
    hostname VARCHAR(255)                       # The FQDN of the client

    ) ENGINE = INNODB;

# Create search indexes for lease6 table
# index by iaid, subnet_id, and duid
CREATE INDEX lease6_by_iaid_subnet_id_duid ON lease6 (iaid, subnet_id, duid);

# ... and a definition of lease6 types.  This table is a convenience for
# users of the database - if they want to view the lease table and use the
# type names, they can join this table with the lease6 table.
# Make sure those values match Lease6::LeaseType enum (see src/bin/dhcpsrv/
# lease_mgr.h)
CREATE TABLE lease6_types (
    lease_type TINYINT PRIMARY KEY NOT NULL,    # Lease type code.
    name VARCHAR(5)                             # Name of the lease type
    ) ENGINE = INNODB;

START TRANSACTION;
INSERT INTO lease6_types VALUES (0, 'IA_NA');   # Non-temporary v6 addresses
INSERT INTO lease6_types VALUES (1, 'IA_TA');   # Temporary v6 addresses
INSERT INTO lease6_types VALUES (2, 'IA_PD');   # Prefix delegations
COMMIT;

# Finally, the version of the schema.  We start at 1.0 during development.
# This table is only modified during schema upgrades.  For historical reasons
# (related to the names of the columns in the BIND 10 DNS database file), the
# first column is called 'version' and not 'major'.
CREATE TABLE schema_version (
    version INT PRIMARY KEY NOT NULL,       # Major version number
    minor INT                               # Minor version number
    ) ENGINE = INNODB;
START TRANSACTION;
INSERT INTO schema_version VALUES (1, 0);
COMMIT;

# This line concludes the schema initialization to version 1.0.

# This line starts the schema upgrade to version 2.0.
ALTER TABLE lease6
    ADD COLUMN hwaddr varbinary(20), # Hardware/MAC address, typically only 6
                                     # bytes is used, but some hardware (e.g.
                                     # Infiniband) use up to 20.
    ADD COLUMN hwtype smallint unsigned, # hardware type (16 bits)
    ADD COLUMN hwaddr_source int unsigned; # Hardware source. See description
                                     # of lease_hwaddr_source below.

# Kea keeps track of the hardware/MAC address source, i.e. how the address
# was obtained. Depending on the technique and your network topology, it may
# be more or less trustworthy. This table is a convenience for
# users of the database - if they want to view the lease table and use the
# type names, they can join this table with the lease6 table. For details,
# see constants defined in src/lib/dhcp/dhcp/pkt.h for detailed explanation.
CREATE TABLE lease_hwaddr_source (
    hwaddr_source INT PRIMARY KEY NOT NULL,
    name VARCHAR(40)
) ENGINE = INNODB;

# Hardware address obtained from raw sockets
INSERT INTO lease_hwaddr_source VALUES (1, 'HWADDR_SOURCE_RAW');

# Hardware address converted from IPv6 link-local address with EUI-64
INSERT INTO lease_hwaddr_source VALUES (2, 'HWADDR_SOURCE_IPV6_LINK_LOCAL');

# Hardware address extracted from client-id (duid)
INSERT INTO lease_hwaddr_source VALUES (4, 'HWADDR_SOURCE_DUID');

# Hardware address extracted from client address relay option (RFC6939)
INSERT INTO lease_hwaddr_source VALUES (8, 'HWADDR_SOURCE_CLIENT_ADDR_RELAY_OPTION');

# Hardware address extracted from remote-id option (RFC4649)
INSERT INTO lease_hwaddr_source VALUES (16, 'HWADDR_SOURCE_REMOTE_ID');

# Hardware address extracted from subscriber-id option (RFC4580)
INSERT INTO lease_hwaddr_source VALUES (32, 'HWADDR_SOURCE_SUBSCRIBER_ID');

# Hardware address extracted from docsis options
INSERT INTO lease_hwaddr_source VALUES (64, 'HWADDR_SOURCE_DOCSIS');

# Update the schema version number
UPDATE schema_version
    SET version = '2', minor = '0';

# This line concludes the schema upgrade to version 2.0.

# This line starts the schema upgrade to version 3.0.

# Upgrade extending MySQL schema with the ability to store hosts.

CREATE TABLE IF NOT EXISTS hosts (
    host_id INT UNSIGNED NOT NULL AUTO_INCREMENT,
    dhcp_identifier VARBINARY(128) NOT NULL,
    dhcp_identifier_type TINYINT NOT NULL,
    dhcp4_subnet_id INT UNSIGNED NULL,
    dhcp6_subnet_id INT UNSIGNED NULL,
    ipv4_address INT UNSIGNED NULL,
    hostname VARCHAR(255) NULL,
    dhcp4_client_classes VARCHAR(255) NULL,
    dhcp6_client_classes VARCHAR(255) NULL,
    PRIMARY KEY (host_id),
    INDEX key_dhcp4_identifier_subnet_id (dhcp_identifier ASC , dhcp_identifier_type ASC),
    INDEX key_dhcp6_identifier_subnet_id (dhcp_identifier ASC , dhcp_identifier_type ASC , dhcp6_subnet_id ASC)
)  ENGINE=INNODB;
-- -----------------------------------------------------
-- Table `ipv6_reservations`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS ipv6_reservations (
    reservation_id INT NOT NULL AUTO_INCREMENT,
    address VARCHAR(39) NOT NULL,
    prefix_len TINYINT(3) UNSIGNED NOT NULL DEFAULT 128,
    type TINYINT(4) UNSIGNED NOT NULL DEFAULT 0,
    dhcp6_iaid INT UNSIGNED NULL,
    host_id INT UNSIGNED NOT NULL,
    PRIMARY KEY (reservation_id),
    INDEX fk_ipv6_reservations_host_idx (host_id ASC),
    CONSTRAINT fk_ipv6_reservations_Host FOREIGN KEY (host_id)
        REFERENCES hosts (host_id)
        ON DELETE NO ACTION ON UPDATE NO ACTION
)  ENGINE=INNODB;
-- -----------------------------------------------------
-- Table `dhcp4_options`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp4_options (
    option_id INT UNSIGNED NOT NULL AUTO_INCREMENT,
    code TINYINT UNSIGNED NOT NULL,
    value BLOB NULL,
    formatted_value TEXT NULL,
    space VARCHAR(128) NULL,
    persistent TINYINT(1) NOT NULL DEFAULT 0,
    dhcp_client_class VARCHAR(128) NULL,
    dhcp4_subnet_id INT NULL,
    host_id INT UNSIGNED NULL,
    PRIMARY KEY (option_id),
    UNIQUE INDEX option_id_UNIQUE (option_id ASC),
    INDEX fk_options_host1_idx (host_id ASC),
    CONSTRAINT fk_options_host1 FOREIGN KEY (host_id)
        REFERENCES hosts (host_id)
        ON DELETE NO ACTION ON UPDATE NO ACTION
)  ENGINE=INNODB;
-- -----------------------------------------------------
-- Table `dhcp6_options`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp6_options (
    option_id INT UNSIGNED NOT NULL AUTO_INCREMENT,
    code INT UNSIGNED NOT NULL,
    value BLOB NULL,
    formatted_value TEXT NULL,
    space VARCHAR(128) NULL,
    persistent TINYINT(1) NOT NULL DEFAULT 0,
    dhcp_client_class VARCHAR(128) NULL,
    dhcp6_subnet_id INT NULL,
    host_id INT UNSIGNED NULL,
    PRIMARY KEY (option_id),
    UNIQUE INDEX option_id_UNIQUE (option_id ASC),
    INDEX fk_options_host1_idx (host_id ASC),
    CONSTRAINT fk_options_host10 FOREIGN KEY (host_id)
        REFERENCES hosts (host_id)
        ON DELETE NO ACTION ON UPDATE NO ACTION
)  ENGINE=INNODB;

DELIMITER $$
CREATE TRIGGER host_BDEL BEFORE DELETE ON hosts FOR EACH ROW
-- Edit trigger body code below this line. Do not edit lines above this one
BEGIN
DELETE FROM ipv6_reservations WHERE ipv6_reservations.host_id = OLD.host_id;
END
$$
DELIMITER ;

# Update the schema version number
UPDATE schema_version
    SET version = '3', minor = '0';

# This line concludes the schema upgrade to version 3.0.

# This line starts the schema upgrade to version 4.0.

# Upgrade extending MySQL schema with the state columns for lease tables.

# Add state column to the lease4 table.
ALTER TABLE lease4
    ADD COLUMN state INT UNSIGNED DEFAULT 0;

# Add state column to the lease6 table.
ALTER TABLE lease6
    ADD COLUMN state INT UNSIGNED DEFAULT 0;

# Create indexes for querying leases in a given state and segregated
# by the expiration time. One of the applications is to retrieve all
# expired leases. However, these indexes can be also used to retrieve
# leases in a given state regardless of the expiration time.
CREATE INDEX lease4_by_state_expire ON lease4 (state ASC, expire ASC);
CREATE INDEX lease6_by_state_expire ON lease6 (state ASC, expire ASC);

# Create table holding mapping of the lease states to their names.
# This is not used in queries from the DHCP server but rather in
# direct queries from the lease database management tools.
CREATE TABLE IF NOT EXISTS lease_state (
  state INT UNSIGNED PRIMARY KEY NOT NULL,
  name VARCHAR(64) NOT NULL
) ENGINE=INNODB;

# Insert currently defined state names.
INSERT INTO lease_state VALUES (0, 'default');
INSERT INTO lease_state VALUES (1, 'declined');
INSERT INTO lease_state VALUES (2, 'expired-reclaimed');

# Add a constraint that any state value added to the lease4 must
# map to a value in the lease_state table.
ALTER TABLE lease4
    ADD CONSTRAINT fk_lease4_state FOREIGN KEY (state)
    REFERENCES lease_state (state);

# Add a constraint that any state value added to the lease6 must
# map to a value in the lease_state table.
ALTER TABLE lease6
    ADD CONSTRAINT fk_lease6_state FOREIGN KEY (state)
    REFERENCES lease_state (state);

# Add a constraint that lease type in the lease6 table must map
# to a lease type defined in the lease6_types table.
ALTER TABLE lease6
    ADD CONSTRAINT fk_lease6_type FOREIGN KEY (lease_type)
    REFERENCES lease6_types (lease_type);

# Modify the name of one of the HW address sources, and add a new one.
UPDATE lease_hwaddr_source
    SET name = 'HWADDR_SOURCE_DOCSIS_CMTS'
    WHERE hwaddr_source = 64;

INSERT INTO lease_hwaddr_source VALUES (128, 'HWADDR_SOURCE_DOCSIS_MODEM');

# Add UNSIGNED to match with the lease6.
ALTER TABLE lease_hwaddr_source
    MODIFY COLUMN hwaddr_source INT UNSIGNED NOT NULL;

# Add a constraint that non-null hwaddr_source in the lease6 table
# must map to an entry in the lease_hwaddr_source.
ALTER TABLE lease6
    ADD CONSTRAINT fk_lease6_hwaddr_source FOREIGN KEY (hwaddr_source)
    REFERENCES lease_hwaddr_source (hwaddr_source);

# Procedure that returns a result set containing the column names for lease4 dumps
DROP PROCEDURE IF EXISTS lease4DumpHeader;
DELIMITER $$
CREATE PROCEDURE lease4DumpHeader()
BEGIN
SELECT 'address,hwaddr,client_id,valid_lifetime,expire,subnet_id,fqdn_fwd,fqdn_rev,hostname,state';
END  $$
DELIMITER ;

# Procedure that returns a result set containing the data for lease4 dumps
DROP PROCEDURE IF EXISTS lease4DumpData;
DELIMITER $$
CREATE PROCEDURE lease4DumpData()
BEGIN
SELECT
    INET_NTOA(l.address),
    IFNULL(HEX(l.hwaddr), ''),
    IFNULL(HEX(l.client_id), ''),
    l.valid_lifetime,
    l.expire,
    l.subnet_id,
    l.fqdn_fwd,
    l.fqdn_rev,
    l.hostname,
    s.name
FROM
    lease4 l
    LEFT OUTER JOIN lease_state s on (l.state = s.state)
ORDER BY l.address;
END $$
DELIMITER ;

# Procedure that returns a result set containing the column names for lease6 dumps
DROP PROCEDURE IF EXISTS lease6DumpHeader;
DELIMITER $$
CREATE PROCEDURE lease6DumpHeader()
BEGIN
SELECT 'address,duid,valid_lifetime,expire,subnet_id,pref_lifetime,lease_type,iaid,prefix_len,fqdn_fwd,fqdn_rev,hostname,hwaddr,hwtype,hwaddr_source,state';
END  $$
DELIMITER ;

# Procedure that returns a result set containing the data for lease6 dumps
DROP PROCEDURE IF EXISTS lease6DumpData;
DELIMITER $$
CREATE PROCEDURE lease6DumpData()
BEGIN
SELECT
    l.address,
    IFNULL(HEX(l.duid), ''),
    l.valid_lifetime,
    l.expire,
    l.subnet_id,
    l.pref_lifetime,
    IFNULL(t.name, ''),
    l.iaid,
    l.prefix_len,
    l.fqdn_fwd,
    l.fqdn_rev,
    l.hostname,
    IFNULL(HEX(l.hwaddr), ''),
    IFNULL(l.hwtype, ''),
    IFNULL(h.name, ''),
    IFNULL(s.name, '')
FROM lease6 l
    left outer join lease6_types t on (l.lease_type = t.lease_type)
    left outer join lease_state s on (l.state = s.state)
    left outer join lease_hwaddr_source h on (l.hwaddr_source = h.hwaddr_source)
ORDER BY l.address;
END $$
DELIMITER ;

# Update the schema version number
UPDATE schema_version
    SET version = '4', minor = '0';

# This line concludes the schema upgrade to version 4.0.

# This line starts the schema upgrade to version 4.1.

# In the event hardware address cannot be determined, we need to satisfy
# foreign key constraint between lease6 and lease_hardware_source
INSERT INTO lease_hwaddr_source VALUES (0, 'HWADDR_SOURCE_UNKNOWN');

# Update the schema version number
UPDATE schema_version
    SET version = '4', minor = '1';

# This line concludes the schema upgrade to version 4.1.

# This line starts the schema upgrade to version 5.

# Update index used for searching DHCPv4 reservations by identifier and subnet id.
# This index is now unique (to prevent duplicates) and includes DHCPv4 subnet
# identifier.
DROP INDEX key_dhcp4_identifier_subnet_id ON hosts;
CREATE UNIQUE INDEX key_dhcp4_identifier_subnet_id ON hosts (dhcp_identifier ASC , dhcp_identifier_type ASC , dhcp4_subnet_id ASC);

# Update index used for searching DHCPv6 reservations by identifier and subnet id.
# This index is now unique to prevent duplicates.
DROP INDEX key_dhcp6_identifier_subnet_id ON hosts;
CREATE UNIQUE INDEX key_dhcp6_identifier_subnet_id ON hosts (dhcp_identifier ASC , dhcp_identifier_type ASC , dhcp6_subnet_id ASC);

# Create index to search for reservations using IP address and subnet id.
# This unique index guarantees that there is only one occurrence of the
# particular IPv4 address for a given subnet.
CREATE UNIQUE INDEX key_dhcp4_ipv4_address_subnet_id ON hosts (ipv4_address ASC , dhcp4_subnet_id ASC);

# Create index to search for reservations using address/prefix and prefix
# length.
CREATE UNIQUE INDEX key_dhcp6_address_prefix_len ON ipv6_reservations (address ASC , prefix_len ASC);

# Create a table mapping host identifiers to their names. Values in this
# table are used as a foreign key in hosts table to guarantee that only
# identifiers present in host_identifier_type table are used in hosts
# table.
CREATE TABLE IF NOT EXISTS host_identifier_type (
    type TINYINT PRIMARY KEY NOT NULL,   # Lease type code.
    name VARCHAR(32)                     # Name of the lease type
) ENGINE = INNODB;

START TRANSACTION;
INSERT INTO host_identifier_type VALUES (0, 'hw-address');
INSERT INTO host_identifier_type VALUES (1, 'duid');
INSERT INTO host_identifier_type VALUES (2, 'circuit-id');
COMMIT;

# Add a constraint that any identifier type value added to the hosts
# must map to a value in the host_identifier_type table.
ALTER TABLE hosts
    ADD CONSTRAINT fk_host_identifier_type FOREIGN KEY (dhcp_identifier_type)
    REFERENCES host_identifier_type (type);

# Store DHCPv6 option code as 16-bit unsigned integer.
ALTER TABLE dhcp6_options MODIFY code SMALLINT UNSIGNED NOT NULL;

# Subnet identifier is unsigned.
ALTER TABLE dhcp4_options MODIFY dhcp4_subnet_id INT UNSIGNED NULL;
ALTER TABLE dhcp6_options MODIFY dhcp6_subnet_id INT UNSIGNED NULL;

# Scopes associate DHCP options stored in dhcp4_options and
# dhcp6_options tables with hosts, subnets, classes or indicate
# that they are global options.
CREATE TABLE IF NOT EXISTS dhcp_option_scope (
    scope_id TINYINT UNSIGNED PRIMARY KEY NOT NULL,
    scope_name VARCHAR(32)
) ENGINE = INNODB;

START TRANSACTION;
INSERT INTO dhcp_option_scope VALUES (0, 'global');
INSERT INTO dhcp_option_scope VALUES (1, 'subnet');
INSERT INTO dhcp_option_scope VALUES (2, 'client-class');
INSERT INTO dhcp_option_scope VALUES (3, 'host');
COMMIT;

# Add scopes into table holding DHCPv4 options
ALTER TABLE dhcp4_options ADD COLUMN scope_id TINYINT UNSIGNED NOT NULL;
ALTER TABLE dhcp4_options
    ADD CONSTRAINT fk_dhcp4_option_scope FOREIGN KEY (scope_id)
    REFERENCES dhcp_option_scope (scope_id);

# Add scopes into table holding DHCPv6 options
ALTER TABLE dhcp6_options ADD COLUMN scope_id TINYINT UNSIGNED NOT NULL;
ALTER TABLE dhcp6_options
    ADD CONSTRAINT fk_dhcp6_option_scope FOREIGN KEY (scope_id)
    REFERENCES dhcp_option_scope (scope_id);

# Add UNSIGNED to reservation_id
ALTER TABLE ipv6_reservations
    MODIFY reservation_id INT UNSIGNED NOT NULL AUTO_INCREMENT;

# Add columns holding reservations for siaddr, sname and file fields
# carried within DHCPv4 message.
ALTER TABLE hosts ADD COLUMN dhcp4_next_server INT UNSIGNED NULL;
ALTER TABLE hosts ADD COLUMN dhcp4_server_hostname VARCHAR(64) NULL;
ALTER TABLE hosts ADD COLUMN dhcp4_boot_file_name VARCHAR(128) NULL;

# Update the schema version number
UPDATE schema_version
    SET version = '5', minor = '0';

# This line concludes the schema upgrade to version 5.0.

# This line starts the schema upgrade to version 5.1.

# Add missing 'client-id' and new 'flex-id' host identifier types.
INSERT INTO host_identifier_type VALUES (3, 'client-id');
INSERT INTO host_identifier_type VALUES (4, 'flex-id');

# Recreate the trigger removing dependent host entries.
DROP TRIGGER host_BDEL;

DELIMITER $$
CREATE TRIGGER host_BDEL BEFORE DELETE ON hosts FOR EACH ROW
-- Edit trigger body code below this line. Do not edit lines above this one
BEGIN
DELETE FROM ipv6_reservations WHERE ipv6_reservations.host_id = OLD.host_id;
DELETE FROM dhcp4_options WHERE dhcp4_options.host_id = OLD.host_id;
DELETE FROM dhcp6_options WHERE dhcp6_options.host_id = OLD.host_id;
END
$$
DELIMITER ;

# Update the schema version number
UPDATE schema_version
    SET version = '5', minor = '1';

# This line concludes the schema upgrade to version 5.1.

# This line starts the schema upgrade to version 5.2.

# Make subnet_id column types consistent with lease table columns
ALTER TABLE dhcp4_options MODIFY dhcp4_subnet_id INT UNSIGNED;
ALTER TABLE dhcp6_options MODIFY dhcp6_subnet_id INT UNSIGNED;

# Update the schema version number
UPDATE schema_version
    SET version = '5', minor = '2';

# This line concludes the schema upgrade to version 5.2.

# This line starts the schema upgrade to version 6.0.

# Add user context into table holding hosts
ALTER TABLE hosts ADD COLUMN user_context TEXT NULL;

# Add user contexts into tables holding DHCP options
ALTER TABLE dhcp4_options ADD COLUMN user_context TEXT NULL;
ALTER TABLE dhcp6_options ADD COLUMN user_context TEXT NULL;

# Create index for searching leases by subnet identifier.
CREATE INDEX lease4_by_subnet_id ON lease4 (subnet_id);

# Create for searching leases by subnet identifier and lease type.
CREATE INDEX lease6_by_subnet_id_lease_type ON lease6 (subnet_id, lease_type);

# The index by iaid_subnet_id_duid is not the best choice because there are
# cases when we don't specify subnet identifier while searching leases. The
# index will be universal if the subnet_id is the right most column in the
# index.
DROP INDEX lease6_by_iaid_subnet_id_duid on lease6;
CREATE INDEX lease6_by_duid_iaid_subnet_id ON lease6 (duid, iaid, subnet_id);

# Create lease4_stat table
CREATE TABLE lease4_stat (
    subnet_id INT UNSIGNED NOT NULL,
    state INT UNSIGNED NOT NULL,
    leases BIGINT,
    PRIMARY KEY (subnet_id, state)
) ENGINE = INNODB;

# Create stat_lease4_insert trigger
DELIMITER $$
CREATE TRIGGER stat_lease4_insert AFTER INSERT ON lease4
    FOR EACH ROW
    BEGIN
        IF NEW.state = 0 OR NEW.state = 1 THEN
            # Update the state count if it exists
            UPDATE lease4_stat SET leases = leases + 1
            WHERE subnet_id = NEW.subnet_id AND state = NEW.state;

            # Insert the state count record if it does not exist
            IF ROW_COUNT() <= 0 THEN
                INSERT INTO lease4_stat VALUES (NEW.subnet_id, NEW.state, 1);
            END IF;
        END IF;
    END $$
DELIMITER ;

# Create stat_lease4_update trigger
DELIMITER $$
CREATE TRIGGER stat_lease4_update AFTER UPDATE ON lease4
    FOR EACH ROW
    BEGIN
        IF OLD.state != NEW.state THEN
            IF OLD.state = 0 OR OLD.state = 1 THEN
                # Decrement the old state count if record exists
                UPDATE lease4_stat SET leases = leases - 1
                WHERE subnet_id = OLD.subnet_id AND state = OLD.state;
            END IF;

            IF NEW.state = 0 OR NEW.state = 1 THEN
                # Increment the new state count if record exists
                UPDATE lease4_stat SET leases = leases + 1
                WHERE subnet_id = NEW.subnet_id AND state = NEW.state;

                # Insert new state record if it does not exist
                IF ROW_COUNT() <= 0 THEN
                    INSERT INTO lease4_stat VALUES (NEW.subnet_id, NEW.state, 1);
                END IF;
            END IF;
        END IF;
    END $$
DELIMITER ;

# Create stat_lease4_delete trigger
DELIMITER $$
CREATE TRIGGER stat_lease4_delete AFTER DELETE ON lease4
    FOR EACH ROW
    BEGIN
        IF OLD.state = 0 OR OLD.state = 1 THEN
            # Decrement the state count if record exists
            UPDATE lease4_stat SET leases = leases - 1
            WHERE subnet_id = OLD.subnet_id AND OLD.state = state;
        END IF;
    END $$
DELIMITER ;

# Create lease6_stat table
CREATE TABLE lease6_stat (
    subnet_id INT UNSIGNED NOT NULL,
    lease_type INT UNSIGNED NOT NULL,
    state INT UNSIGNED NOT NULL,
    leases BIGINT,
    PRIMARY KEY (subnet_id, lease_type, state)
) ENGINE = INNODB;

# Create stat_lease6_insert trigger
DELIMITER $$
CREATE TRIGGER stat_lease6_insert AFTER INSERT ON lease6
    FOR EACH ROW
    BEGIN
        IF NEW.state = 0 OR NEW.state = 1 THEN
            # Update the state count if it exists
            UPDATE lease6_stat SET leases = leases + 1
            WHERE
                subnet_id = NEW.subnet_id AND lease_type = NEW.lease_type
                AND state = NEW.state;

            # Insert the state count record if it does not exist
            IF ROW_COUNT() <= 0 THEN
                INSERT INTO lease6_stat
                VALUES (NEW.subnet_id, NEW.lease_type, NEW.state, 1);
            END IF;
        END IF;
    END $$
DELIMITER ;

# Create stat_lease6_update trigger
DELIMITER $$
CREATE TRIGGER stat_lease6_update AFTER UPDATE ON lease6
    FOR EACH ROW
    BEGIN
        IF OLD.state != NEW.state THEN
            IF OLD.state = 0 OR OLD.state = 1 THEN
                # Decrement the old state count if record exists
                UPDATE lease6_stat SET leases = leases - 1
                WHERE subnet_id = OLD.subnet_id AND lease_type = OLD.lease_type
                AND state = OLD.state;
            END IF;

            IF NEW.state = 0 OR NEW.state = 1 THEN
                # Increment the new state count if record exists
                UPDATE lease6_stat SET leases = leases + 1
                WHERE subnet_id = NEW.subnet_id AND lease_type = NEW.lease_type
                AND state = NEW.state;

                # Insert new state record if it does not exist
                IF ROW_COUNT() <= 0 THEN
                    INSERT INTO lease6_stat
                    VALUES (NEW.subnet_id, NEW.lease_type, NEW.state, 1);
                END IF;
            END IF;
        END IF;
    END $$
DELIMITER ;

# Create stat_lease6_delete trigger
DELIMITER $$
CREATE TRIGGER stat_lease6_delete AFTER DELETE ON lease6
    FOR EACH ROW
    BEGIN
        IF OLD.state = 0 OR OLD.state = 1 THEN
            # Decrement the state count if record exists
            UPDATE lease6_stat SET leases = leases - 1
            WHERE subnet_id = OLD.subnet_id AND lease_type = OLD.lease_type
            AND state = OLD.state;
        END IF;
    END $$
DELIMITER ;

# Update the schema version number
UPDATE schema_version
    SET version = '6', minor = '0';

# This line concludes the schema upgrade to version 6.0.

# This line starts the schema upgrade to version 7.0.

# Add user context into tables holding leases
ALTER TABLE lease4 ADD COLUMN user_context TEXT NULL;
ALTER TABLE lease6 ADD COLUMN user_context TEXT NULL;

DROP PROCEDURE IF EXISTS lease4DumpHeader;
DELIMITER $$
CREATE PROCEDURE lease4DumpHeader()
BEGIN
SELECT 'address,hwaddr,client_id,valid_lifetime,expire,subnet_id,fqdn_fwd,fqdn_rev,hostname,state,user_context';
END  $$
DELIMITER ;

# Procedure that returns a result set containing the data for lease4 dumps
DROP PROCEDURE IF EXISTS lease4DumpData;
DELIMITER $$
CREATE PROCEDURE lease4DumpData()
BEGIN
SELECT
    INET_NTOA(l.address),
    IFNULL(HEX(l.hwaddr), ''),
    IFNULL(HEX(l.client_id), ''),
    l.valid_lifetime,
    l.expire,
    l.subnet_id,
    l.fqdn_fwd,
    l.fqdn_rev,
    l.hostname,
    s.name,
    IFNULL(l.user_context, '')
FROM
    lease4 l
    LEFT OUTER JOIN lease_state s on (l.state = s.state)
ORDER BY l.address;
END $$
DELIMITER ;

DROP PROCEDURE IF EXISTS lease6DumpHeader;
DELIMITER $$
CREATE PROCEDURE lease6DumpHeader()
BEGIN
SELECT 'address,duid,valid_lifetime,expire,subnet_id,pref_lifetime,lease_type,iaid,prefix_len,fqdn_fwd,fqdn_rev,hostname,hwaddr,hwtype,hwaddr_source,state,user_context';
END  $$
DELIMITER ;

# Procedure that returns a result set containing the data for lease6 dumps
DROP PROCEDURE IF EXISTS lease6DumpData;
DELIMITER $$
CREATE PROCEDURE lease6DumpData()
BEGIN
SELECT
    l.address,
    IFNULL(HEX(l.duid), ''),
    l.valid_lifetime,
    l.expire,
    l.subnet_id,
    l.pref_lifetime,
    IFNULL(t.name, ''),
    l.iaid,
    l.prefix_len,
    l.fqdn_fwd,
    l.fqdn_rev,
    l.hostname,
    IFNULL(HEX(l.hwaddr), ''),
    IFNULL(l.hwtype, ''),
    IFNULL(h.name, ''),
    IFNULL(s.name, ''),
    IFNULL(l.user_context, '')
FROM lease6 l
    left outer join lease6_types t on (l.lease_type = t.lease_type)
    left outer join lease_state s on (l.state = s.state)
    left outer join lease_hwaddr_source h on (l.hwaddr_source = h.hwaddr_source)
ORDER BY l.address;
END $$
DELIMITER ;

# Create logs table (logs table is used by forensic logging hook library)
CREATE TABLE logs (
    timestamp TIMESTAMP DEFAULT CURRENT_TIMESTAMP,  # creation timestamp
    address VARCHAR(43) NULL,                       # address or prefix
    log TEXT NOT NULL                               # the log itself
    ) ENGINE = INNODB;

# Create search index
CREATE INDEX timestamp_index ON logs (timestamp);

#add auth key for reconfiguration
ALTER TABLE hosts
    ADD COLUMN auth_key VARCHAR(16) NULL;

# Add scope for shared network specific options.
INSERT INTO dhcp_option_scope (scope_id, scope_name)
    VALUES(4, "shared-network");

# Add scope for pool specific options.
INSERT INTO dhcp_option_scope (scope_id, scope_name)
    VALUES(5, "pool");

# Add scope for PD pool specific options.
INSERT INTO dhcp_option_scope (scope_id, scope_name)
    VALUES(6, "pd-pool");

-- -----------------------------------------------------
-- Table `modification`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS modification (
  id TINYINT(3) NOT NULL,
  modification_type VARCHAR(32) NOT NULL,
  PRIMARY KEY (id)
) ENGINE=InnoDB;

INSERT INTO modification(id, modification_type)
    VALUES(0, "create");

INSERT INTO modification(id, modification_type)
    VALUES(1, "update");

INSERT INTO modification(id, modification_type)
    VALUES(2, "delete");

-- -----------------------------------------------------
-- Table `dhcp4_server`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp4_server (
    id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
    tag VARCHAR(64) NOT NULL,
    description TEXT,
    modification_ts TIMESTAMP NOT NULL,
    PRIMARY KEY (id),
    UNIQUE KEY dhcp4_server_tag_UNIQUE (tag),
    KEY key_dhcp4_server_modification_ts (modification_ts)
) ENGINE=InnoDB;

# Special server entry meaning "all servers". This refers to
# the configuration entries owned by all servers.
INSERT INTO dhcp4_server(id, tag, description, modification_ts)
    VALUES(1, "all", "special type: all servers", NOW());

-- -----------------------------------------------------
-- Table `dhcp4_audit`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp4_audit (
    id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
    object_type VARCHAR(256) NOT NULL,
    object_id BIGINT(20) UNSIGNED NOT NULL,
    modification_type TINYINT(1) NOT NULL,
    modification_ts TIMESTAMP NOT NULL,
    log_message TEXT,
    PRIMARY KEY (id),
    KEY key_dhcp4_audit_by_modification_ts (modification_ts),
    KEY fk_dhcp4_audit_modification_type (modification_type),
    CONSTRAINT fk_dhcp4_audit_modification_type FOREIGN KEY (modification_type)
        REFERENCES modification (id)
        ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB;

-- -----------------------------------------------------
-- Table `dhcp4_global_parameter`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp4_global_parameter (
    id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
    name VARCHAR(128) NOT NULL,
    value LONGTEXT NOT NULL,
    modification_ts timestamp NOT NULL,
    PRIMARY KEY (id),
    KEY key_dhcp4_global_parameter_modification_ts (modification_ts),
    KEY key_dhcp4_global_parameter_name (name)
) ENGINE=InnoDB;

-- -----------------------------------------------------
-- Table `dhcp4_global_parameter_server`
-- M-to-M cross-reference between global parameters and
-- servers
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp4_global_parameter_server (
    parameter_id BIGINT(20) UNSIGNED NOT NULL,
    server_id BIGINT(20) UNSIGNED NOT NULL,
    modification_ts TIMESTAMP NOT NULL,
    PRIMARY KEY (parameter_id, server_id),
    KEY fk_dhcp4_global_parameter_server_server_id (server_id),
    KEY key_dhcp4_global_parameter_server (modification_ts),
    CONSTRAINT fk_dhcp4_global_parameter_server_parameter_id FOREIGN KEY (parameter_id)
        REFERENCES dhcp4_global_parameter (id)
        ON DELETE CASCADE ON UPDATE NO ACTION,
    CONSTRAINT fk_dhcp4_global_parameter_server_server_id FOREIGN KEY (server_id)
        REFERENCES dhcp4_server (id)
        ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB;

-- -----------------------------------------------------
-- Table `dhcp4_option_def`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp4_option_def (
    id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
    code SMALLINT UNSIGNED NOT NULL,
    name VARCHAR(128) NOT NULL,
    space VARCHAR(128) NOT NULL,
    type TINYINT UNSIGNED NOT NULL,
    modification_ts TIMESTAMP NOT NULL,
    is_array TINYINT(1) NOT NULL,
    encapsulate VARCHAR(128) NOT NULL,
    record_types VARCHAR(512) DEFAULT NULL,
    user_context LONGTEXT,
    PRIMARY KEY (id),
    KEY key_dhcp4_option_def_modification_ts (modification_ts),
    KEY key_dhcp4_option_def_code_space (code, space)
) ENGINE=InnoDB;

-- -----------------------------------------------------
-- Table `dhcp4_option_def_server`
-- M-to-M cross-reference between option definitions and
-- servers
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp4_option_def_server (
    option_def_id BIGINT(20) UNSIGNED NOT NULL,
    server_id BIGINT(20) UNSIGNED NOT NULL,
    modification_ts TIMESTAMP NOT NULL,
    PRIMARY KEY (option_def_id, server_id),
    KEY fk_dhcp4_option_def_server_server_id_idx (server_id),
    KEY key_dhcp4_option_def_server_modification_ts (modification_ts),
    CONSTRAINT fk_dhcp4_option_def_server_option_def_id FOREIGN KEY (option_def_id)
        REFERENCES dhcp4_option_def (id)
        ON DELETE CASCADE ON UPDATE NO ACTION,
    CONSTRAINT fk_dhcp4_option_def_server_server_id FOREIGN KEY (server_id)
        REFERENCES dhcp4_server (id) ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB;

-- -----------------------------------------------------
-- Table `dhcp4_shared_network`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp4_shared_network (
    id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
    name VARCHAR(128) NOT NULL,
    client_class VARCHAR(128) DEFAULT NULL,
    interface VARCHAR(128) DEFAULT NULL,
    match_client_id TINYINT(1) NOT NULL DEFAULT '1',
    modification_ts TIMESTAMP NOT NULL,
    rebind_timer INT(10) DEFAULT NULL,
    relay LONGTEXT,
    renew_timer INT(10) DEFAULT NULL,
    require_client_classes LONGTEXT DEFAULT NULL,
    reservation_mode TINYINT(3) NOT NULL DEFAULT '3',
    user_context LONGTEXT,
    valid_lifetime INT(10) DEFAULT NULL,
    PRIMARY KEY (id),
    UNIQUE KEY name_UNIQUE (name),
    KEY key_dhcp4_shared_network_modification_ts (modification_ts)
) ENGINE=InnoDB;

-- -----------------------------------------------------
-- Table `dhcp4_shared_network_server`
-- M-to-M cross-reference between shared networks and
-- servers
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp4_shared_network_server (
    shared_network_id BIGINT(20) UNSIGNED NOT NULL,
    server_id BIGINT(20) UNSIGNED NOT NULL,
    modification_ts TIMESTAMP NOT NULL,
    PRIMARY KEY (shared_network_id, server_id),
    KEY key_dhcp4_shared_network_server_modification_ts (modification_ts),
    KEY fk_dhcp4_shared_network_server_server_id (server_id),
    CONSTRAINT fk_dhcp4_shared_network_server_server_id FOREIGN KEY (server_id)
        REFERENCES dhcp4_server (id)
        ON DELETE NO ACTION ON UPDATE NO ACTION,
    CONSTRAINT fk_dhcp4_shared_network_server_shared_network_id FOREIGN KEY (shared_network_id)
        REFERENCES dhcp4_shared_network (id) ON DELETE CASCADE ON UPDATE NO ACTION
) ENGINE=InnoDB;

-- -----------------------------------------------------
-- Table `dhcp4_subnet`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp4_subnet (
    subnet_id INT(10) UNSIGNED NOT NULL,
    subnet_prefix VARCHAR(32) NOT NULL,
    4o6_interface VARCHAR(128) DEFAULT NULL,
    4o6_interface_id VARCHAR(128) DEFAULT NULL,
    4o6_subnet VARCHAR(64) DEFAULT NULL,
    boot_file_name VARCHAR(512) DEFAULT NULL,
    client_class VARCHAR(128) DEFAULT NULL,
    interface VARCHAR(128) DEFAULT NULL,
    match_client_id TINYINT(1) NOT NULL DEFAULT '1',
    modification_ts TIMESTAMP NOT NULL,
    next_server INT(10) UNSIGNED DEFAULT NULL,
    rebind_timer INT(10) DEFAULT NULL,
    relay LONGTEXT,
    renew_timer INT(10) DEFAULT NULL,
    require_client_classes LONGTEXT DEFAULT NULL,
    reservation_mode TINYINT(3) NOT NULL DEFAULT '3',
    server_hostname VARCHAR(512) DEFAULT NULL,
    shared_network_name VARCHAR(128) DEFAULT NULL,
    user_context LONGTEXT,
    valid_lifetime INT(10) DEFAULT NULL,
    PRIMARY KEY (subnet_id),
    UNIQUE KEY subnet4_subnet_prefix (subnet_prefix),
    KEY fk_dhcp4_subnet_shared_network (shared_network_name),
    KEY key_dhcp4_subnet_modification_ts (modification_ts),
    CONSTRAINT fk_dhcp4_subnet_shared_network FOREIGN KEY (shared_network_name)
        REFERENCES dhcp4_shared_network (name)
        ON DELETE SET NULL ON UPDATE NO ACTION
) ENGINE=InnoDB;

-- -----------------------------------------------------
-- Table `dhcp4_pool`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp4_pool (
    id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
    start_address INT(10) UNSIGNED NOT NULL,
    end_address INT(10) UNSIGNED NOT NULL,
    subnet_id INT(10) UNSIGNED NOT NULL,
    modification_ts TIMESTAMP NOT NULL,
    PRIMARY KEY (id),
    KEY key_dhcp4_pool_modification_ts (modification_ts),
    KEY fk_dhcp4_pool_subnet_id (subnet_id),
    CONSTRAINT fk_dhcp4_pool_subnet_id FOREIGN KEY (subnet_id)
        REFERENCES dhcp4_subnet (subnet_id)
        ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB;

-- -----------------------------------------------------
-- Table `dhcp4_subnet_server`
-- M-to-M cross-reference between subnets and servers
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp4_subnet_server (
    subnet_id INT(10) UNSIGNED NOT NULL,
    server_id BIGINT(20) UNSIGNED NOT NULL,
    modification_ts TIMESTAMP NOT NULL,
    PRIMARY KEY (subnet_id,server_id),
    KEY fk_dhcp4_subnet_server_server_id_idx (server_id),
    KEY key_dhcp4_subnet_server_modification_ts (modification_ts),
    CONSTRAINT fk_dhcp4_subnet_server_server_id FOREIGN KEY (server_id)
        REFERENCES dhcp4_server (id)
        ON DELETE NO ACTION ON UPDATE NO ACTION,
    CONSTRAINT fk_dhcp4_subnet_server_subnet_id FOREIGN KEY (subnet_id)
        REFERENCES dhcp4_subnet (subnet_id)
        ON DELETE CASCADE ON UPDATE NO ACTION
) ENGINE=InnoDB;

# Modify the primary key to BINGINT as other tables have.
ALTER TABLE dhcp4_options MODIFY option_id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT;

# Add configuration backend specific columns.
ALTER TABLE dhcp4_options
    ADD COLUMN shared_network_name VARCHAR(128) DEFAULT NULL,
    ADD COLUMN pool_id BIGINT(20) UNSIGNED DEFAULT NULL,
    ADD COLUMN modification_ts TIMESTAMP NOT NULL;

-- -----------------------------------------------------
-- Table `dhcp4_options_server`
-- M-to-M cross-reference between options and servers
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp4_options_server (
    option_id BIGINT(20) UNSIGNED NOT NULL,
    server_id BIGINT(20) UNSIGNED NOT NULL,
    modification_ts TIMESTAMP NOT NULL,
    PRIMARY KEY (option_id, server_id),
    KEY fk_dhcp4_options_server_server_id (server_id),
    KEY key_dhcp4_options_server_modification_ts (modification_ts),
    CONSTRAINT fk_dhcp4_options_server_option_id FOREIGN KEY (option_id)
        REFERENCES dhcp4_options (option_id)
        ON DELETE CASCADE ON UPDATE NO ACTION,
    CONSTRAINT fk_dhcp4_options_server_server_id FOREIGN KEY (server_id)
        REFERENCES dhcp4_server (id)
        ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB;

# Create trigger which removes pool specific options upon removal of
# the pool.
DELIMITER $$
CREATE TRIGGER dhcp4_pool_BDEL BEFORE DELETE ON dhcp4_pool FOR EACH ROW
-- Edit trigger body code below this line. Do not edit lines above this one
BEGIN
DELETE FROM dhcp4_options WHERE scope_id = 5 AND pool_id = OLD.id;
END
$$
DELIMITER ;

-- -----------------------------------------------------
-- Table `dhcp6_server`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp6_server (
    id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
    tag VARCHAR(64) NOT NULL,
    description TEXT,
    modification_ts TIMESTAMP NOT NULL,
    PRIMARY KEY (id),
    UNIQUE KEY dhcp6_server_tag_UNIQUE (tag),
    KEY key_dhcp6_server_modification_ts (modification_ts)
) ENGINE=InnoDB;

# Special server entry meaning "all servers". This refers to
# the configuration entries owned by all servers.
INSERT INTO dhcp6_server(id, tag, description, modification_ts)
    VALUES(1, "all", "special type: all servers", NOW());

-- -----------------------------------------------------
-- Table `dhcp6_audit`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp6_audit (
    id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
    object_type VARCHAR(256) NOT NULL,
    object_id BIGINT(20) UNSIGNED NOT NULL,
    modification_type TINYINT(1) NOT NULL,
    modification_ts TIMESTAMP NOT NULL,
    log_message TEXT,
    PRIMARY KEY (id),
    KEY key_dhcp6_audit_modification_ts (modification_ts),
    KEY fk_dhcp6_audit_modification_type (modification_type),
    CONSTRAINT fk_dhcp6_audit_modification_type FOREIGN KEY (modification_type)
        REFERENCES modification (id)
        ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB;

-- -----------------------------------------------------
-- Table `dhcp6_global_parameter`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp6_global_parameter (
    id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
    name VARCHAR(128) NOT NULL,
    value LONGTEXT NOT NULL,
    modification_ts timestamp NOT NULL,
    PRIMARY KEY (id),
    KEY key_dhcp6_global_parameter_modification_ts (modification_ts),
    KEY key_dhcp6_global_parameter_name (name)
) ENGINE=InnoDB;

-- -----------------------------------------------------
-- Table `dhcp6_global_parameter_server`
-- M-to-M cross-reference between global parameters and
-- servers
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp6_global_parameter_server (
    parameter_id BIGINT(20) UNSIGNED NOT NULL,
    server_id BIGINT(20) UNSIGNED NOT NULL,
    modification_ts TIMESTAMP NOT NULL,
    PRIMARY KEY (parameter_id, server_id),
    KEY fk_dhcp6_global_parameter_server_server_id (server_id),
    KEY key_dhcp6_global_parameter_server (modification_ts),
    CONSTRAINT fk_dhcp6_global_parameter_server_parameter_id FOREIGN KEY (parameter_id)
        REFERENCES dhcp6_global_parameter (id)
        ON DELETE CASCADE ON UPDATE NO ACTION,
    CONSTRAINT fk_dhcp6_global_parameter_server_server_id FOREIGN KEY (server_id)
        REFERENCES dhcp6_server (id)
        ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB;

-- -----------------------------------------------------
-- Table `dhcp6_option_def`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp6_option_def (
    id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
    code SMALLINT UNSIGNED NOT NULL,
    name VARCHAR(128) NOT NULL,
    space VARCHAR(128) NOT NULL,
    type TINYINT UNSIGNED NOT NULL,
    modification_ts TIMESTAMP NOT NULL,
    is_array TINYINT(1) NOT NULL,
    encapsulate VARCHAR(128) NOT NULL,
    record_types VARCHAR(512) DEFAULT NULL,
    user_context LONGTEXT,
    PRIMARY KEY (id),
    KEY key_dhcp6_option_def_modification_ts (modification_ts),
    KEY key_dhcp6_option_def_code_space (code, space)
) ENGINE=InnoDB;

-- -----------------------------------------------------
-- Table `dhcp6_option_def_server`
-- M-to-M cross-reference between option definitions and
-- servers
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp6_option_def_server (
    option_def_id BIGINT(20) UNSIGNED NOT NULL,
    server_id BIGINT(20) UNSIGNED NOT NULL,
    modification_ts TIMESTAMP NOT NULL,
    PRIMARY KEY (option_def_id, server_id),
    KEY fk_dhcp6_option_def_server_server_id_idx (server_id),
    KEY key_dhcp6_option_def_server_modification_ts (modification_ts),
    CONSTRAINT fk_dhcp6_option_def_server_option_def_id FOREIGN KEY (option_def_id)
        REFERENCES dhcp6_option_def (id)
        ON DELETE CASCADE ON UPDATE NO ACTION,
    CONSTRAINT fk_dhcp6_option_def_server_server_id FOREIGN KEY (server_id)
        REFERENCES dhcp6_server (id) ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB;

-- -----------------------------------------------------
-- Table `dhcp6_shared_network`
-- -----------------------------------------------------
CREATE TABLE dhcp6_shared_network (
    id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
    name VARCHAR(128) NOT NULL,
    client_class VARCHAR(128) DEFAULT NULL,
    interface VARCHAR(128) DEFAULT NULL,
    modification_ts TIMESTAMP NOT NULL,
    preferred_lifetime INT(10) DEFAULT NULL,
    rapid_commit TINYINT(1) NOT NULL DEFAULT '1',
    rebind_timer INT(10) DEFAULT NULL,
    relay LONGTEXT DEFAULT NULL,
    renew_timer INT(10) DEFAULT NULL,
    require_client_classes LONGTEXT,
    reservation_mode TINYINT(3) NOT NULL DEFAULT '3',
    user_context LONGTEXT,
    valid_lifetime INT(10) DEFAULT NULL,
    PRIMARY KEY (id),
    UNIQUE KEY name_UNIQUE (name),
    KEY key_dhcp6_shared_network_modification_ts (modification_ts)
) ENGINE=InnoDB;

-- -----------------------------------------------------
-- Table `dhcp6_shared_network_server`
-- M-to-M cross-reference between shared networks and
-- servers
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp6_shared_network_server (
    shared_network_id BIGINT(20) UNSIGNED NOT NULL,
    server_id BIGINT(20) UNSIGNED NOT NULL,
    modification_ts TIMESTAMP NOT NULL,
    KEY key_dhcp6_shared_network_server_modification_ts (modification_ts),
    KEY fk_dhcp6_shared_network_server_server_id_idx (server_id),
    KEY fk_dhcp6_shared_network_server_shared_network_id (shared_network_id),
    CONSTRAINT fk_dhcp6_shared_network_server_server_id FOREIGN KEY (server_id)
        REFERENCES dhcp6_server (id)
        ON DELETE NO ACTION ON UPDATE NO ACTION,
    CONSTRAINT fk_dhcp6_shared_network_server_shared_network_id FOREIGN KEY (shared_network_id)
        REFERENCES dhcp6_shared_network (id)
        ON DELETE CASCADE ON UPDATE NO ACTION
) ENGINE=InnoDB;

-- -----------------------------------------------------
-- Table `dhcp6_subnet`
-- -----------------------------------------------------
CREATE TABLE dhcp6_subnet (
    subnet_id INT(10) UNSIGNED NOT NULL,
    subnet_prefix VARCHAR(64) NOT NULL,
    client_class VARCHAR(128) DEFAULT NULL,
    interface VARCHAR(128) DEFAULT NULL,
    modification_ts TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
    preferred_lifetime INT(10) DEFAULT NULL,
    rapid_commit TINYINT(1) NOT NULL DEFAULT '1',
    rebind_timer INT(10) DEFAULT NULL,
    relay LONGTEXT DEFAULT NULL,
    renew_timer INT(10) DEFAULT NULL,
    require_client_classes LONGTEXT,
    reservation_mode TINYINT(3) NOT NULL DEFAULT '3',
    shared_network_name VARCHAR(128) DEFAULT NULL,
    user_context LONGTEXT,
    valid_lifetime INT(10) DEFAULT NULL,
    PRIMARY KEY (subnet_id),
    UNIQUE KEY subnet_prefix_UNIQUE (subnet_prefix),
    KEY subnet6_subnet_prefix (subnet_prefix),
    KEY fk_dhcp6_subnet_shared_network (shared_network_name),
    KEY key_dhcp6_subnet_modification_ts (modification_ts),
    CONSTRAINT fk_dhcp6_subnet_shared_network FOREIGN KEY (shared_network_name)
        REFERENCES dhcp6_shared_network (name)
        ON DELETE SET NULL ON UPDATE NO ACTION
) ENGINE=InnoDB;

-- -----------------------------------------------------
-- Table `dhcp6_subnet_server`
-- M-to-M cross-reference between subnets and servers
-- -----------------------------------------------------
CREATE TABLE dhcp6_subnet_server (
    subnet_id INT(10) UNSIGNED NOT NULL,
    server_id BIGINT(20) UNSIGNED NOT NULL,
    modification_ts TIMESTAMP NOT NULL,
    PRIMARY KEY (subnet_id, server_id),
    KEY fk_dhcp6_subnet_server_server_id (server_id),
    KEY key_dhcp6_subnet_server_modification_ts (modification_ts),
    CONSTRAINT fk_dhcp6_subnet_server_server_id FOREIGN KEY (server_id)
        REFERENCES dhcp6_server (id)
        ON DELETE NO ACTION ON UPDATE NO ACTION,
    CONSTRAINT fk_dhcp6_subnet_server_subnet_id FOREIGN KEY (subnet_id)
        REFERENCES dhcp6_subnet (subnet_id)
        ON DELETE CASCADE ON UPDATE NO ACTION
) ENGINE=InnoDB;

-- -----------------------------------------------------
-- Table `dhcp6_pd_pool`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp6_pd_pool (
    id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
    prefix VARCHAR(45) NOT NULL,
    prefix_length TINYINT(3) NOT NULL,
    delegated_prefix_length TINYINT(3) NOT NULL,
    dhcp6_subnet_id INT(10) UNSIGNED NOT NULL,
    modification_ts TIMESTAMP NOT NULL,
    PRIMARY KEY (id),
    KEY fk_dhcp6_pd_pool_subnet_id (dhcp6_subnet_id),
    KEY key_dhcp6_pd_pool_modification_ts (modification_ts),
    CONSTRAINT fk_dhcp6_pd_pool_subnet_id FOREIGN KEY (dhcp6_subnet_id)
        REFERENCES dhcp6_subnet (subnet_id) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB;

-- -----------------------------------------------------
-- Table `dhcp6_pool`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp6_pool (
    id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
    start_address VARCHAR(45) NOT NULL,
    end_address VARCHAR(45) NOT NULL,
    dhcp6_subnet_id INT(10) UNSIGNED NOT NULL,
    modification_ts TIMESTAMP NOT NULL,
    PRIMARY KEY (id),
    KEY fk_dhcp6_pool_subnet_id (dhcp6_subnet_id),
    KEY key_dhcp6_pool_modification_ts (modification_ts),
    CONSTRAINT fk_dhcp6_pool_subnet_id FOREIGN KEY (dhcp6_subnet_id)
        REFERENCES dhcp6_subnet (subnet_id) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB;

# Modify the primary key to BINGINT as other tables have.
ALTER TABLE dhcp6_options MODIFY option_id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT;

# Add configuration backend specific columns.
ALTER TABLE dhcp6_options
    ADD COLUMN shared_network_name VARCHAR(128) DEFAULT NULL,
    ADD COLUMN pool_id BIGINT(20) UNSIGNED DEFAULT NULL,
    ADD COLUMN pd_pool_id BIGINT(20) UNSIGNED DEFAULT NULL,
    ADD COLUMN modification_ts TIMESTAMP NOT NULL;

-- -----------------------------------------------------
-- Table `dhcp6_options_server`
-- M-to-M cross-reference between options and servers
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp6_options_server (
    option_id BIGINT(20) UNSIGNED NOT NULL,
    server_id BIGINT(20) UNSIGNED NOT NULL,
    modification_ts TIMESTAMP NOT NULL,
    PRIMARY KEY (option_id, server_id),
    KEY fk_dhcp6_options_server_server_id_idx (server_id),
    KEY key_dhcp6_options_server_modification_ts (modification_ts),
    CONSTRAINT fk_dhcp6_options_server_option_id FOREIGN KEY (option_id)
        REFERENCES dhcp6_options (option_id)
        ON DELETE NO ACTION ON UPDATE NO ACTION,
    CONSTRAINT fk_dhcp6_options_server_server_id FOREIGN KEY (server_id)
        REFERENCES dhcp6_server (id)
        ON DELETE CASCADE ON UPDATE NO ACTION
) ENGINE=InnoDB;

# Create trigger which removes pool specific options upon removal of
# the pool.
DELIMITER $$
CREATE TRIGGER dhcp6_pool_BDEL BEFORE DELETE ON dhcp6_pool FOR EACH ROW
-- Edit trigger body code below this line. Do not edit lines above this one
BEGIN
DELETE FROM dhcp6_options WHERE scope_id = 5 AND pool_id = OLD.id;
END
$$
DELIMITER ;

# Update the schema version number
UPDATE schema_version
    SET version = '7', minor = '0';

# This line concludes the schema upgrade to version 7.0.

# This line starts the schema upgrade to version 8.0.

ALTER TABLE dhcp4_options
    MODIFY COLUMN modification_ts TIMESTAMP NOT NULL
    DEFAULT CURRENT_TIMESTAMP;

ALTER TABLE dhcp6_options
    MODIFY COLUMN modification_ts TIMESTAMP NOT NULL
    DEFAULT CURRENT_TIMESTAMP;

ALTER TABLE dhcp4_subnet
    ADD COLUMN authoritative TINYINT(1) DEFAULT NULL,
    ADD COLUMN calculate_tee_times TINYINT(1) DEFAULT NULL,
    ADD COLUMN t1_percent FLOAT DEFAULT NULL,
    ADD COLUMN t2_percent FLOAT DEFAULT NULL;

ALTER TABLE dhcp4_subnet
    MODIFY COLUMN reservation_mode TINYINT(3) DEFAULT NULL;

ALTER TABLE dhcp4_subnet
    MODIFY COLUMN match_client_id TINYINT(1) DEFAULT NULL;

ALTER TABLE dhcp4_shared_network
    ADD COLUMN authoritative TINYINT(1) DEFAULT NULL,
    ADD COLUMN calculate_tee_times TINYINT(1) DEFAULT NULL,
    ADD COLUMN t1_percent FLOAT DEFAULT NULL,
    ADD COLUMN t2_percent FLOAT DEFAULT NULL,
    ADD COLUMN boot_file_name VARCHAR(512) DEFAULT NULL,
    ADD COLUMN next_server INT(10) UNSIGNED DEFAULT NULL,
    ADD COLUMN server_hostname VARCHAR(512) DEFAULT NULL;

ALTER TABLE dhcp4_shared_network
    MODIFY COLUMN reservation_mode TINYINT(3) DEFAULT NULL;

ALTER TABLE dhcp4_shared_network
    MODIFY COLUMN match_client_id TINYINT(1) DEFAULT NULL;

ALTER TABLE dhcp6_subnet
    ADD COLUMN calculate_tee_times TINYINT(1) DEFAULT NULL,
    ADD COLUMN t1_percent FLOAT DEFAULT NULL,
    ADD COLUMN t2_percent FLOAT DEFAULT NULL,
    ADD COLUMN interface_id VARBINARY(128) DEFAULT NULL;

ALTER TABLE dhcp6_subnet
    MODIFY COLUMN reservation_mode TINYINT(3) DEFAULT NULL;

ALTER TABLE dhcp6_subnet
    MODIFY COLUMN rapid_commit TINYINT(1) DEFAULT NULL;

ALTER TABLE dhcp6_shared_network
    ADD COLUMN calculate_tee_times TINYINT(1) DEFAULT NULL,
    ADD COLUMN t1_percent FLOAT DEFAULT NULL,
    ADD COLUMN t2_percent FLOAT DEFAULT NULL,
    ADD COLUMN interface_id VARBINARY(128) DEFAULT NULL;

ALTER TABLE dhcp6_shared_network
    MODIFY COLUMN reservation_mode TINYINT(3) DEFAULT NULL;

ALTER TABLE dhcp6_shared_network
    MODIFY COLUMN rapid_commit TINYINT(1) DEFAULT NULL;

-- -----------------------------------------------------
-- Make sure that constraints on the 7.0 schema tables
-- have appropriate referential actions. All tables
-- which join the configuration elements with the
-- servers should perform cascade deletion.
-- -----------------------------------------------------

ALTER TABLE dhcp4_global_parameter_server
    DROP FOREIGN KEY fk_dhcp4_global_parameter_server_server_id;

ALTER TABLE dhcp4_global_parameter_server
    ADD CONSTRAINT fk_dhcp4_global_parameter_server_server_id
        FOREIGN KEY (server_id)
    REFERENCES dhcp4_server (id)
    ON DELETE CASCADE ON UPDATE NO ACTION;

ALTER TABLE dhcp4_option_def_server
    DROP FOREIGN KEY fk_dhcp4_option_def_server_server_id;

ALTER TABLE dhcp4_option_def_server
    ADD CONSTRAINT fk_dhcp4_option_def_server_server_id
        FOREIGN KEY (server_id)
    REFERENCES dhcp4_server (id)
    ON DELETE CASCADE ON UPDATE NO ACTION;

ALTER TABLE dhcp4_shared_network_server
    DROP FOREIGN KEY fk_dhcp4_shared_network_server_server_id;

ALTER TABLE dhcp4_shared_network_server
    ADD CONSTRAINT fk_dhcp4_shared_network_server_server_id
        FOREIGN KEY (server_id)
    REFERENCES dhcp4_server (id)
    ON DELETE CASCADE ON UPDATE NO ACTION;

ALTER TABLE dhcp4_subnet_server
    DROP FOREIGN KEY fk_dhcp4_subnet_server_server_id;

ALTER TABLE dhcp4_subnet_server
    ADD CONSTRAINT fk_dhcp4_subnet_server_server_id
        FOREIGN KEY (server_id)
    REFERENCES dhcp4_server (id)
    ON DELETE CASCADE ON UPDATE NO ACTION;

ALTER TABLE dhcp4_options_server
    DROP FOREIGN KEY fk_dhcp4_options_server_server_id;

ALTER TABLE dhcp4_options_server
    ADD CONSTRAINT fk_dhcp4_options_server_server_id
        FOREIGN KEY (server_id)
    REFERENCES dhcp4_server (id)
    ON DELETE CASCADE ON UPDATE NO ACTION;

ALTER TABLE dhcp6_global_parameter_server
    DROP FOREIGN KEY fk_dhcp6_global_parameter_server_server_id;

ALTER TABLE dhcp6_global_parameter_server
    ADD CONSTRAINT fk_dhcp6_global_parameter_server_server_id
        FOREIGN KEY (server_id)
    REFERENCES dhcp6_server (id)
    ON DELETE CASCADE ON UPDATE NO ACTION;

ALTER TABLE dhcp6_option_def_server
    DROP FOREIGN KEY fk_dhcp6_option_def_server_server_id;

ALTER TABLE dhcp6_option_def_server
    ADD CONSTRAINT fk_dhcp6_option_def_server_server_id
        FOREIGN KEY (server_id)
    REFERENCES dhcp6_server (id)
    ON DELETE CASCADE ON UPDATE NO ACTION;

ALTER TABLE dhcp6_shared_network_server
    DROP FOREIGN KEY fk_dhcp6_shared_network_server_server_id;

ALTER TABLE dhcp6_shared_network_server
    ADD CONSTRAINT fk_dhcp6_shared_network_server_server_id
        FOREIGN KEY (server_id)
    REFERENCES dhcp6_server (id)
    ON DELETE CASCADE ON UPDATE NO ACTION;

ALTER TABLE dhcp6_subnet_server
    DROP FOREIGN KEY fk_dhcp6_subnet_server_server_id;

ALTER TABLE dhcp6_subnet_server
    ADD CONSTRAINT fk_dhcp6_subnet_server_server_id
        FOREIGN KEY (server_id)
    REFERENCES dhcp6_server (id)
    ON DELETE CASCADE ON UPDATE NO ACTION;

ALTER TABLE dhcp6_options_server
    DROP FOREIGN KEY fk_dhcp6_options_server_option_id;

ALTER TABLE dhcp6_options_server
    ADD CONSTRAINT fk_dhcp6_options_server_option_id
        FOREIGN KEY (option_id)
    REFERENCES dhcp6_options (option_id)
    ON DELETE CASCADE ON UPDATE NO ACTION;

-- -----------------------------------------------------
-- Table `dhcp4_audit_revision`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp4_audit_revision (
    id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
    modification_ts TIMESTAMP NOT NULL,
    log_message TEXT,
    server_id BIGINT(10) UNSIGNED,
    PRIMARY KEY (id),
    KEY key_dhcp4_audit_revision_by_modification_ts (modification_ts)
) ENGINE=InnoDB;

-- -----------------------------------------------------
-- Drop columns from the dhcp4_audit table which now
-- belong to the dhcp4_audit_revision.
-- -----------------------------------------------------
ALTER TABLE dhcp4_audit
    DROP COLUMN modification_ts,
    DROP COLUMN log_message;

-- -----------------------------------------------------
-- Add column revision_id and the foreign key with a
-- reference to the dhcp4_audit_revision table.
-- -----------------------------------------------------
ALTER TABLE dhcp4_audit
    ADD COLUMN revision_id BIGINT(20) UNSIGNED NOT NULL;

ALTER TABLE dhcp4_audit
    ADD CONSTRAINT fk_dhcp4_audit_revision FOREIGN KEY (revision_id)
        REFERENCES dhcp4_audit_revision (id)
        ON DELETE NO ACTION ON UPDATE CASCADE;

-- -----------------------------------------------------
-- Stored procedure which creates a new entry in the
-- dhcp4_audit_revision table and sets appropriate session
-- variables to be used while creating the audit entries
-- by triggers. This procedure should be called at the
-- beginning of a transaction which modifies configuration
-- data in the database, e.g. when new subnet is added.
--
-- Parameters:
-- - audit_ts timestamp to be associated with the audit
--   revision.
-- - server_tag is used to retrieve the server_id which
--   associates the changes applied with the particular
--   server or all servers.
-- - audit_log_message is a log message associates with
--   the audit revision.
-- - cascade_transaction is assigned to a session
--   variable which is used in some triggers to determine
--   if the audit entry should be created for them or
--   not. Specifically, this is used when DHCP options
--   are inserted, updated or deleted. If such modification
--   is a part of the larger change (e.g. change in the
--   subnet the options belong to) the dedicated audit
--   entry for options must not be created. On the other
--   hand, if the global option is being added, the
--   audit entry for the option must be created because
--   it is the sole object modified in that case.
--   Session variable disable_audit is used to disable
--   the procedure when wiping the database during
--   unit tests.  This avoids issues with revision_id
--   being null.
-- -----------------------------------------------------
DROP PROCEDURE IF EXISTS createAuditRevisionDHCP4;
DELIMITER $$
CREATE PROCEDURE createAuditRevisionDHCP4(IN audit_ts TIMESTAMP,
                                          IN server_tag VARCHAR(256),
                                          IN audit_log_message TEXT,
                                          IN cascade_transaction TINYINT(1))
BEGIN
    DECLARE srv_id BIGINT(20);
    IF @disable_audit IS NULL OR @disable_audit = 0 THEN
        SELECT id INTO srv_id FROM dhcp4_server WHERE tag = server_tag;
        INSERT INTO dhcp4_audit_revision (modification_ts, server_id, log_message)
            VALUES (audit_ts, srv_id, audit_log_message);
        SET @audit_revision_id = LAST_INSERT_ID();
        SET @cascade_transaction = cascade_transaction;
    END IF;
END $$
DELIMITER ;

-- -----------------------------------------------------
-- Stored procedure which creates a new entry in the
-- dhcp4_audit table. It should be called from the
-- triggers of the tables where the config modifications
-- are applied. The @audit_revision_id variable contains
-- the revision id to be placed in the audit entries.
--
-- The following parameters are passed to this procedure:
-- - object_type_val: name of the table to be associated
--   with the applied changes.
-- - object_id_val: identifier of the modified object in
--   that table.
-- - modification_type_val: string value indicating the
--   type of the change, i.e. "create", "update" or
--   "delete".
--   Session variable disable_audit is used to disable
--   the procedure when wiping the database during
--   unit tests.  This avoids issues with revision_id
--   being null.
-- ----------------------------------------------------
DROP PROCEDURE IF EXISTS createAuditEntryDHCP4;
DELIMITER $$
CREATE PROCEDURE createAuditEntryDHCP4(IN object_type_val VARCHAR(256),
                                       IN object_id_val BIGINT(20) UNSIGNED,
                                       IN modification_type_val VARCHAR(32))
BEGIN
    IF @disable_audit IS NULL OR @disable_audit = 0 THEN
        INSERT INTO dhcp4_audit (object_type, object_id, modification_type, revision_id)
            VALUES (object_type_val, object_id_val, \
               (SELECT id FROM modification WHERE modification_type = modification_type_val), \
                @audit_revision_id);
    END IF;
END $$
DELIMITER ;

-- -----------------------------------------------------
-- Triggers used to create entries in the audit
-- tables upon insertion, update or deletion of the
-- configuration entries.
-- -----------------------------------------------------

# Create dhcp4_global_parameter insert trigger
DELIMITER $$
CREATE TRIGGER dhcp4_global_parameter_AINS AFTER INSERT ON dhcp4_global_parameter
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP4('dhcp4_global_parameter', NEW.id, "create");
    END $$
DELIMITER ;

# Create dhcp4_global_parameter update trigger
DELIMITER $$
CREATE TRIGGER dhcp4_global_parameter_AUPD AFTER UPDATE ON dhcp4_global_parameter
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP4('dhcp4_global_parameter', NEW.id, "update");
    END $$
DELIMITER ;

# Create dhcp4_global_parameter delete trigger
DELIMITER $$
CREATE TRIGGER dhcp4_global_parameter_ADEL AFTER DELETE ON dhcp4_global_parameter
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP4('dhcp4_global_parameter', OLD.id, "delete");
    END $$
DELIMITER ;

# Create dhcp4_subnet insert trigger
DELIMITER $$
CREATE TRIGGER dhcp4_subnet_AINS AFTER INSERT ON dhcp4_subnet
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP4('dhcp4_subnet', NEW.subnet_id, "create");
    END $$
DELIMITER ;

# Create dhcp4_subnet update trigger
DELIMITER $$
CREATE TRIGGER dhcp4_subnet_AUPD AFTER UPDATE ON dhcp4_subnet
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP4('dhcp4_subnet', NEW.subnet_id, "update");
    END $$
DELIMITER ;

# Create dhcp4_subnet delete trigger
DELIMITER $$
CREATE TRIGGER dhcp4_subnet_ADEL AFTER DELETE ON dhcp4_subnet
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP4('dhcp4_subnet', OLD.subnet_id, "delete");
    END $$
DELIMITER ;

# Create dhcp4_shared_network insert trigger
DELIMITER $$
CREATE TRIGGER dhcp4_shared_network_AINS AFTER INSERT ON dhcp4_shared_network
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP4('dhcp4_shared_network', NEW.id, "create");
    END $$
DELIMITER ;

# Create dhcp4_shared_network update trigger
DELIMITER $$
CREATE TRIGGER dhcp4_shared_network_AUPD AFTER UPDATE ON dhcp4_shared_network
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP4('dhcp4_shared_network', NEW.id, "update");
    END $$
DELIMITER ;

# Create dhcp4_shared_network delete trigger
DELIMITER $$
CREATE TRIGGER dhcp4_shared_network_ADEL AFTER DELETE ON dhcp4_shared_network
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP4('dhcp4_shared_network', OLD.id, "delete");
    END $$
DELIMITER ;

# Create dhcp4_option_def insert trigger
DELIMITER $$
CREATE TRIGGER dhcp4_option_def_AINS AFTER INSERT ON dhcp4_option_def
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP4('dhcp4_option_def', NEW.id, "create");
    END $$
DELIMITER ;

# Create dhcp4_option_def update trigger
DELIMITER $$
CREATE TRIGGER dhcp4_option_def_AUPD AFTER UPDATE ON dhcp4_option_def
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP4('dhcp4_option_def', NEW.id, "update");
    END $$
DELIMITER ;

# Create dhcp4_option_def delete trigger
DELIMITER $$
CREATE TRIGGER dhcp4_option_def_ADEL AFTER DELETE ON dhcp4_option_def
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP4('dhcp4_option_def', OLD.id, "delete");
    END $$
DELIMITER ;

-- -----------------------------------------------------
-- Stored procedure which creates an audit entry for a
-- DHCPv4 option. Depending on the scope of the option
-- the audit entry can be created for various levels
-- of configuration hierarchy. If this is a global
-- option the audit entry is created for this option
-- for CREATE, UPDATE or DELETE. If the option is being
-- added for an owning option, e.g. for a subnet, the
-- audit entry is created as an UPDATE to this object.
-- From the Kea perspective such option addition will
-- be seen as a subnet update and the server will fetch
-- the whole subnet and merge it into its configuration.
-- The audit entry is not created if it was already
-- created as part of the current transaction.
--
-- The following parameters are passed to the procedure:
-- - modification_type: "create", "update" or "delete"
-- - scope_id: identifier of the option scope, e.g.
--   global, subnet specific etc. See dhcp_option_scope
--   for specific values.
-- - option_id: identifier of the option.
-- - subnet_id: identifier of the subnet if the option
--   belongs to the subnet.
-- - host_id: identifier of the host if the option
-- - belongs to the host.
-- - network_name: shared network name if the option
--   belongs to the shared network.
-- - pool_id: identifier of the pool if the option
--   belongs to the pool.
-- -----------------------------------------------------
DROP PROCEDURE IF EXISTS createOptionAuditDHCP4;
DELIMITER $$
CREATE PROCEDURE createOptionAuditDHCP4(IN modification_type VARCHAR(32),
                                        IN scope_id TINYINT(3) UNSIGNED,
                                        IN option_id BIGINT(20) UNSIGNED,
                                        IN subnet_id INT(10) UNSIGNED,
                                        IN host_id INT(10) UNSIGNED,
                                        IN network_name VARCHAR(128),
                                        IN pool_id BIGINT(20))
BEGIN
    # These variables will hold shared network id and subnet id that
    # we will select.
    DECLARE snid VARCHAR(128);
    DECLARE sid INT(10) UNSIGNED;

    # Cascade transaction flag is set to 1 to prevent creation of
    # the audit entries for the options when the options are
    # created as part of the parent object creation or update.
    # For example: when the option is added as part of the subnet
    # addition, the cascade transaction flag is equal to 1. If
    # the option is added into the existing subnet the cascade
    # transaction is equal to 0. Note that depending on the option
    # scope the audit entry will contain the object_type value
    # of the parent object to cause the server to replace the
    # entire subnet. The only case when the object_type will be
    # set to 'dhcp4_options' is when a global option is added.
    # Global options do not have the owner.
    IF @cascade_transaction IS NULL OR @cascade_transaction = 0 THEN
        # todo: host manager hasn't been updated to use audit
        # mechanisms so ignore host specific options for now.
        IF scope_id = 0 THEN
            # If a global option is added or modified, create audit
            # entry for the 'dhcp4_options' table.
            CALL createAuditEntryDHCP4('dhcp4_options', option_id, modification_type);
        ELSEIF scope_id = 1 THEN
            # If subnet specific option is added or modified, create
            # audit entry for the entire subnet, which indicates that
            # it should be treated as the subnet update.
            CALL createAuditEntryDHCP4('dhcp4_subnet', subnet_id, "update");
        ELSEIF scope_id = 4 THEN
            # If shared network specific option is added or modified,
            # create audit entry for the shared network which
            # indicates that it should be treated as the shared
            # network update.
           SELECT id INTO snid FROM dhcp4_shared_network WHERE name = network_name LIMIT 1;
           CALL createAuditEntryDHCP4('dhcp4_shared_network', snid, "update");
        ELSEIF scope_id = 5 THEN
            # If pool specific option is added or modified, create
            # audit entry for the subnet which this pool belongs to.
            SELECT dhcp4_pool.subnet_id INTO sid FROM dhcp4_pool WHERE id = pool_id;
            CALL createAuditEntryDHCP4('dhcp4_subnet', sid, "update");
        END IF;
    END IF;
END $$
DELIMITER ;

# Create dhcp4_options insert trigger
DELIMITER $$
CREATE TRIGGER dhcp4_options_AINS AFTER INSERT ON dhcp4_options
    FOR EACH ROW
    BEGIN
        CALL createOptionAuditDHCP4("create", NEW.scope_id, NEW.option_id, NEW.dhcp4_subnet_id,
                                    NEW.host_id, NEW.shared_network_name, NEW.pool_id);
    END $$
DELIMITER ;

# Create dhcp4_options update trigger
DELIMITER $$
CREATE TRIGGER dhcp4_options_AUPD AFTER UPDATE ON dhcp4_options
    FOR EACH ROW
    BEGIN
        CALL createOptionAuditDHCP4("update", NEW.scope_id, NEW.option_id, NEW.dhcp4_subnet_id,
                                    NEW.host_id, NEW.shared_network_name, NEW.pool_id);
    END $$
DELIMITER ;

# Create dhcp4_options delete trigger
DELIMITER $$
CREATE TRIGGER dhcp4_options_ADEL AFTER DELETE ON dhcp4_options
    FOR EACH ROW
    BEGIN
        CALL createOptionAuditDHCP4("delete", OLD.scope_id, OLD.option_id, OLD.dhcp4_subnet_id,
                                    OLD.host_id, OLD.shared_network_name, OLD.pool_id);
    END $$
DELIMITER ;

-- -----------------------------------------------------
-- Table `parameter_data_type`
-- Reflects an enum used by Kea to define supported
-- data types for the simple configuration parameters,
-- e.g. global parameters used by DHCP servers.
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS parameter_data_type (
    id TINYINT UNSIGNED NOT NULL PRIMARY KEY,
    name VARCHAR(32) NOT NULL
) ENGINE = InnoDB;

START TRANSACTION;
INSERT INTO parameter_data_type VALUES (0, 'integer');
INSERT INTO parameter_data_type VALUES (1, 'real');
INSERT INTO parameter_data_type VALUES (2, 'boolean');
INSERT INTO parameter_data_type VALUES (4, 'string');
COMMIT;

ALTER TABLE dhcp4_global_parameter
    ADD COLUMN parameter_type TINYINT UNSIGNED NOT NULL;

ALTER TABLE dhcp4_global_parameter
    ADD CONSTRAINT fk_dhcp4_global_parameter_type FOREIGN KEY (parameter_type)
        REFERENCES parameter_data_type (id);

ALTER TABLE dhcp6_global_parameter
    ADD COLUMN parameter_type TINYINT UNSIGNED NOT NULL;

ALTER TABLE dhcp6_global_parameter
    ADD CONSTRAINT fk_dhcp6_global_parameter_type FOREIGN KEY (parameter_type)
        REFERENCES parameter_data_type (id);

-- Rename dhcp6_subnet_id column of dhcp6_pool and dhcp6_pd_pool

ALTER TABLE dhcp6_pool
    DROP FOREIGN KEY fk_dhcp6_pool_subnet_id;
DROP INDEX fk_dhcp6_pool_subnet_id
    ON dhcp6_pool;

ALTER TABLE dhcp6_pd_pool
    DROP FOREIGN KEY fk_dhcp6_pd_pool_subnet_id;
DROP INDEX fk_dhcp6_pd_pool_subnet_id
    ON dhcp6_pd_pool;

ALTER TABLE dhcp6_pool
    CHANGE dhcp6_subnet_id subnet_id INT(10) UNSIGNED NOT NULL;

ALTER TABLE dhcp6_pd_pool
    CHANGE dhcp6_subnet_id subnet_id INT(10) UNSIGNED NOT NULL;

ALTER TABLE dhcp6_pool
    ADD CONSTRAINT fk_dhcp6_pool_subnet_id
    FOREIGN KEY (subnet_id)
    REFERENCES dhcp6_subnet (subnet_id)
    ON DELETE CASCADE ON UPDATE CASCADE;

ALTER TABLE dhcp6_pd_pool
    ADD CONSTRAINT fk_dhcp6_pd_pool_subnet_id
    FOREIGN KEY (subnet_id)
    REFERENCES dhcp6_subnet (subnet_id)
    ON DELETE CASCADE ON UPDATE CASCADE;

-- align dhcp6_shared_network_server indexes on dhcp4_shared_network_server

ALTER TABLE dhcp6_shared_network_server
    ADD PRIMARY KEY (shared_network_id, server_id);

ALTER TABLE dhcp6_shared_network_server
    DROP FOREIGN KEY fk_dhcp6_shared_network_server_shared_network_id;
DROP INDEX fk_dhcp6_shared_network_server_shared_network_id
    ON dhcp6_shared_network_server;
ALTER TABLE dhcp6_shared_network_server
    ADD CONSTRAINT fk_dhcp6_shared_network_server_shared_network_id
    FOREIGN KEY (shared_network_id)
    REFERENCES dhcp6_shared_network (id)
    ON DELETE CASCADE ON UPDATE NO ACTION;

-- Update dhcp4_subnet_server and dhcp6_subnet_server to allow update
-- on the prefix too by setting the CASCADE action.

ALTER TABLE dhcp4_subnet_server
    DROP FOREIGN KEY fk_dhcp4_subnet_server_subnet_id;
ALTER TABLE dhcp4_subnet_server
    ADD CONSTRAINT fk_dhcp4_subnet_server_subnet_id FOREIGN KEY (subnet_id)
    REFERENCES dhcp4_subnet (subnet_id)
    ON DELETE CASCADE ON UPDATE CASCADE;

ALTER TABLE dhcp6_subnet_server
    DROP FOREIGN KEY fk_dhcp6_subnet_server_subnet_id;
ALTER TABLE dhcp6_subnet_server
    ADD CONSTRAINT fk_dhcp6_subnet_server_subnet_id FOREIGN KEY (subnet_id)
    REFERENCES dhcp6_subnet (subnet_id)
    ON DELETE CASCADE ON UPDATE CASCADE;

-- -----------------------------------------------------
-- Table `dhcp6_audit_revision`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp6_audit_revision (
    id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
    modification_ts TIMESTAMP NOT NULL,
    log_message TEXT,
    server_id BIGINT(10) UNSIGNED,
    PRIMARY KEY (id),
    KEY key_dhcp6_audit_revision_by_modification_ts (modification_ts)
) ENGINE=InnoDB;

-- -----------------------------------------------------
-- Drop columns from the dhcp6_audit table which now
-- belong to the dhcp6_audit_revision.
-- -----------------------------------------------------
ALTER TABLE dhcp6_audit
    DROP COLUMN modification_ts,
    DROP COLUMN log_message;

-- -----------------------------------------------------
-- Add column revision_id and the foreign key with a
-- reference to the dhcp6_audit_revision table.
-- -----------------------------------------------------
ALTER TABLE dhcp6_audit
    ADD COLUMN revision_id BIGINT(20) UNSIGNED NOT NULL;

ALTER TABLE dhcp6_audit
    ADD CONSTRAINT fk_dhcp6_audit_revision FOREIGN KEY (revision_id)
        REFERENCES dhcp6_audit_revision (id)
        ON DELETE NO ACTION ON UPDATE CASCADE;

-- -----------------------------------------------------
-- Stored procedure which creates a new entry in the
-- dhcp6_audit_revision table and sets appropriate session
-- variables to be used while creating the audit entries
-- by triggers. This procedure should be called at the
-- beginning of a transaction which modifies configuration
-- data in the database, e.g. when new subnet is added.
--
-- Parameters:
-- - audit_ts timestamp to be associated with the audit
--   revision.
-- - server_tag is used to retrieve the server_id which
--   associates the changes applied with the particular
--   server or all servers.
-- - audit_log_message is a log message associates with
--   the audit revision.
-- - cascade_transaction is assigned to a session
--   variable which is used in some triggers to determine
--   if the audit entry should be created for them or
--   not. Specifically, this is used when DHCP options
--   are inserted, updated or deleted. If such modification
--   is a part of the larger change (e.g. change in the
--   subnet the options belong to) the dedicated audit
--   entry for options must not be created. On the other
--   hand, if the global option is being added, the
--   audit entry for the option must be created because
--   it is the sole object modified in that case.
--   Session variable disable_audit is used to disable
--   the procedure when wiping the database during
--   unit tests.  This avoids issues with revision_id
--   being null.
-- -----------------------------------------------------
DROP PROCEDURE IF EXISTS createAuditRevisionDHCP6;
DELIMITER $$
CREATE PROCEDURE createAuditRevisionDHCP6(IN audit_ts TIMESTAMP,
                                          IN server_tag VARCHAR(256),
                                          IN audit_log_message TEXT,
                                          IN cascade_transaction TINYINT(1))
BEGIN
    DECLARE srv_id BIGINT(20);
    IF @disable_audit IS NULL OR @disable_audit = 0 THEN
        SELECT id INTO srv_id FROM dhcp6_server WHERE tag = server_tag;
        INSERT INTO dhcp6_audit_revision (modification_ts, server_id, log_message)
            VALUES (audit_ts, srv_id, audit_log_message);
        SET @audit_revision_id = LAST_INSERT_ID();
        SET @cascade_transaction = cascade_transaction;
    END IF;
END $$
DELIMITER ;

-- -----------------------------------------------------
-- Stored procedure which creates a new entry in the
-- dhcp6_audit table. It should be called from the
-- triggers of the tables where the config modifications
-- are applied. The @audit_revision_id variable contains
-- the revision id to be placed in the audit entries.
--
-- The following parameters are passed to this procedure:
-- - object_type_val: name of the table to be associated
--   with the applied changes.
-- - object_id_val: identifier of the modified object in
--   that table.
-- - modification_type_val: string value indicating the
--   type of the change, i.e. "create", "update" or
--   "delete".
--   Session variable disable_audit is used to disable
--   the procedure when wiping the database during
--   unit tests.  This avoids issues with revision_id
--   being null.
-- ----------------------------------------------------
DROP PROCEDURE IF EXISTS createAuditEntryDHCP6;
DELIMITER $$
CREATE PROCEDURE createAuditEntryDHCP6(IN object_type_val VARCHAR(256),
                                       IN object_id_val BIGINT(20) UNSIGNED,
                                       IN modification_type_val VARCHAR(32))
BEGIN
    IF @disable_audit IS NULL OR @disable_audit = 0 THEN
        INSERT INTO dhcp6_audit (object_type, object_id, modification_type, revision_id)
            VALUES (object_type_val, object_id_val, \
               (SELECT id FROM modification WHERE modification_type = modification_type_val), \
                @audit_revision_id);
    END IF;
END $$
DELIMITER ;

-- -----------------------------------------------------
-- Triggers used to create entries in the audit
-- tables upon insertion, update or deletion of the
-- configuration entries.
-- -----------------------------------------------------

# Create dhcp6_global_parameter insert trigger
DELIMITER $$
CREATE TRIGGER dhcp6_global_parameter_AINS AFTER INSERT ON dhcp6_global_parameter
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP6('dhcp6_global_parameter', NEW.id, "create");
    END $$
DELIMITER ;

# Create dhcp6_global_parameter update trigger
DELIMITER $$
CREATE TRIGGER dhcp6_global_parameter_AUPD AFTER UPDATE ON dhcp6_global_parameter
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP6('dhcp6_global_parameter', NEW.id, "update");
    END $$
DELIMITER ;

# Create dhcp6_global_parameter delete trigger
DELIMITER $$
CREATE TRIGGER dhcp6_global_parameter_ADEL AFTER DELETE ON dhcp6_global_parameter
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP6('dhcp6_global_parameter', OLD.id, "delete");
    END $$
DELIMITER ;

# Create dhcp6_subnet insert trigger
DELIMITER $$
CREATE TRIGGER dhcp6_subnet_AINS AFTER INSERT ON dhcp6_subnet
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP6('dhcp6_subnet', NEW.subnet_id, "create");
    END $$
DELIMITER ;

# Create dhcp6_subnet update trigger
DELIMITER $$
CREATE TRIGGER dhcp6_subnet_AUPD AFTER UPDATE ON dhcp6_subnet
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP6('dhcp6_subnet', NEW.subnet_id, "update");
    END $$
DELIMITER ;

# Create dhcp6_subnet delete trigger
DELIMITER $$
CREATE TRIGGER dhcp6_subnet_ADEL AFTER DELETE ON dhcp6_subnet
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP6('dhcp6_subnet', OLD.subnet_id, "delete");
    END $$
DELIMITER ;

# Create dhcp6_shared_network insert trigger
DELIMITER $$
CREATE TRIGGER dhcp6_shared_network_AINS AFTER INSERT ON dhcp6_shared_network
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP6('dhcp6_shared_network', NEW.id, "create");
    END $$
DELIMITER ;

# Create dhcp6_shared_network update trigger
DELIMITER $$
CREATE TRIGGER dhcp6_shared_network_AUPD AFTER UPDATE ON dhcp6_shared_network
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP6('dhcp6_shared_network', NEW.id, "update");
    END $$
DELIMITER ;

# Create dhcp6_shared_network delete trigger
DELIMITER $$
CREATE TRIGGER dhcp6_shared_network_ADEL AFTER DELETE ON dhcp6_shared_network
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP6('dhcp6_shared_network', OLD.id, "delete");
    END $$
DELIMITER ;

# Create dhcp6_option_def insert trigger
DELIMITER $$
CREATE TRIGGER dhcp6_option_def_AINS AFTER INSERT ON dhcp6_option_def
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP6('dhcp6_option_def', NEW.id, "create");
    END $$
DELIMITER ;

# Create dhcp6_option_def update trigger
DELIMITER $$
CREATE TRIGGER dhcp6_option_def_AUPD AFTER UPDATE ON dhcp6_option_def
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP6('dhcp6_option_def', NEW.id, "update");
    END $$
DELIMITER ;

# Create dhcp6_option_def delete trigger
DELIMITER $$
CREATE TRIGGER dhcp6_option_def_ADEL AFTER DELETE ON dhcp6_option_def
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP6('dhcp6_option_def', OLD.id, "delete");
    END $$
DELIMITER ;

-- -----------------------------------------------------
-- Stored procedure which creates an audit entry for a
-- DHCPv6 option. Depending on the scope of the option
-- the audit entry can be created for various levels
-- of configuration hierarchy. If this is a global
-- option the audit entry is created for this option
-- for CREATE, UPDATE or DELETE. If the option is being
-- added for an owning option, e.g. for a subnet, the
-- audit entry is created as an UPDATE to this object.
-- From the Kea perspective such option addition will
-- be seen as a subnet update and the server will fetch
-- the whole subnet and merge it into its configuration.
-- The audit entry is not created if it was already
-- created as part of the current transaction.
--
-- The following parameters are passed to the procedure:
-- - modification_type: "create", "update" or "delete"
-- - scope_id: identifier of the option scope, e.g.
--   global, subnet specific etc.
-- - option_id: identifier of the option.
-- - subnet_id: identifier of the subnet if the option
--   belongs to the subnet.
-- - host_id: identifier of the host if the option
-- - belongs to the host.
-- - network_name: shared network name if the option
--   belongs to the shared network.
-- - pool_id: identifier of the pool if the option
--   belongs to the pool.
-- - pd_pool_id: identifier of the pool if the option
--   belongs to the pd pool.
-- -----------------------------------------------------
DROP PROCEDURE IF EXISTS createOptionAuditDHCP6;
DELIMITER $$
CREATE PROCEDURE createOptionAuditDHCP6(IN modification_type VARCHAR(32),
                                        IN scope_id TINYINT(3) UNSIGNED,
                                        IN option_id BIGINT(20) UNSIGNED,
                                        IN subnet_id INT(10) UNSIGNED,
                                        IN host_id INT(10) UNSIGNED,
                                        IN network_name VARCHAR(128),
                                        IN pool_id BIGINT(20),
                                        IN pd_pool_id BIGINT(20))
BEGIN
    # These variables will hold shared network id and subnet id that
    # we will select.
    DECLARE snid VARCHAR(128);
    DECLARE sid INT(10) UNSIGNED;

    # Cascade transaction flag is set to 1 to prevent creation of
    # the audit entries for the options when the options are
    # created as part of the parent object creation or update.
    # For example: when the option is added as part of the subnet
    # addition, the cascade transaction flag is equal to 1. If
    # the option is added into the existing subnet the cascade
    # transaction is equal to 0. Note that depending on the option
    # scope the audit entry will contain the object_type value
    # of the parent object to cause the server to replace the
    # entire subnet. The only case when the object_type will be
    # set to 'dhcp6_options' is when a global option is added.
    # Global options do not have the owner.
    IF @cascade_transaction IS NULL OR @cascade_transaction = 0 THEN
        # todo: host manager hasn't been updated to use audit
        # mechanisms so ignore host specific options for now.
        IF scope_id = 0 THEN
            # If a global option is added or modified, create audit
            # entry for the 'dhcp6_options' table.
            CALL createAuditEntryDHCP6('dhcp6_options', option_id, modification_type);
        ELSEIF scope_id = 1 THEN
            # If subnet specific option is added or modified, create
            # audit entry for the entire subnet, which indicates that
            # it should be treated as the subnet update.
            CALL createAuditEntryDHCP6('dhcp6_subnet', subnet_id, "update");
        ELSEIF scope_id = 4 THEN
            # If shared network specific option is added or modified,
            # create audit entry for the shared network which
            # indicates that it should be treated as the shared
            # network update.
           SELECT id INTO snid FROM dhcp6_shared_network WHERE name = network_name LIMIT 1;
           CALL createAuditEntryDHCP6('dhcp6_shared_network', snid, "update");
        ELSEIF scope_id = 5 THEN
            # If pool specific option is added or modified, create
            # audit entry for the subnet which this pool belongs to.
            SELECT dhcp6_pool.subnet_id INTO sid FROM dhcp6_pool WHERE id = pool_id;
            CALL createAuditEntryDHCP6('dhcp6_subnet', sid, "update");
        ELSEIF scope_id = 6 THEN
            # If pd pool specific option is added or modified, create
            # audit entry for the subnet which this pd pool belongs to.
            SELECT dhcp6_pd_pool.subnet_id INTO sid FROM dhcp6_pd_pool WHERE id = pd_pool_id;
            CALL createAuditEntryDHCP6('dhcp6_subnet', sid, "update");
        END IF;
    END IF;
END $$
DELIMITER ;

# Create dhcp6_options insert trigger
DELIMITER $$
CREATE TRIGGER dhcp6_options_AINS AFTER INSERT ON dhcp6_options
    FOR EACH ROW
    BEGIN
        CALL createOptionAuditDHCP6("create", NEW.scope_id, NEW.option_id, NEW.dhcp6_subnet_id,
                                    NEW.host_id, NEW.shared_network_name, NEW.pool_id, NEW.pd_pool_id);
    END $$
DELIMITER ;

# Create dhcp6_options update trigger
DELIMITER $$
CREATE TRIGGER dhcp6_options_AUPD AFTER UPDATE ON dhcp6_options
    FOR EACH ROW
    BEGIN
        CALL createOptionAuditDHCP6("update", NEW.scope_id, NEW.option_id, NEW.dhcp6_subnet_id,
                                    NEW.host_id, NEW.shared_network_name, NEW.pool_id, NEW.pd_pool_id);
    END $$
DELIMITER ;

# Create dhcp6_options delete trigger
DELIMITER $$
CREATE TRIGGER dhcp6_options_ADEL AFTER DELETE ON dhcp6_options
    FOR EACH ROW
    BEGIN
        CALL createOptionAuditDHCP6("delete", OLD.scope_id, OLD.option_id, OLD.dhcp6_subnet_id,
                                    OLD.host_id, OLD.shared_network_name, OLD.pool_id, OLD.pd_pool_id);
    END $$
DELIMITER ;

# Update the schema version number
UPDATE schema_version
    SET version = '8', minor = '0';

# This line concludes the schema upgrade to version 8.0.

# This line starts the schema upgrade to version 8.1.

# Add lifetime bounds
ALTER TABLE dhcp4_shared_network
    ADD COLUMN min_valid_lifetime INT(10) DEFAULT NULL,
    ADD COLUMN max_valid_lifetime INT(10) DEFAULT NULL;

ALTER TABLE dhcp4_subnet
    ADD COLUMN min_valid_lifetime INT(10) DEFAULT NULL,
    ADD COLUMN max_valid_lifetime INT(10) DEFAULT NULL;

ALTER TABLE dhcp6_shared_network
    ADD COLUMN min_preferred_lifetime INT(10) DEFAULT NULL,
    ADD COLUMN max_preferred_lifetime INT(10) DEFAULT NULL,
    ADD COLUMN min_valid_lifetime INT(10) DEFAULT NULL,
    ADD COLUMN max_valid_lifetime INT(10) DEFAULT NULL;

ALTER TABLE dhcp6_subnet
    ADD COLUMN min_preferred_lifetime INT(10) DEFAULT NULL,
    ADD COLUMN max_preferred_lifetime INT(10) DEFAULT NULL,
    ADD COLUMN min_valid_lifetime INT(10) DEFAULT NULL,
    ADD COLUMN max_valid_lifetime INT(10) DEFAULT NULL;

# Create dhcp4_server insert trigger
DELIMITER $$
CREATE TRIGGER dhcp4_server_AINS AFTER INSERT ON dhcp4_server
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP4('dhcp4_server', NEW.id, "create");
    END $$
DELIMITER ;

# Create dhcp4_server update trigger
DELIMITER $$
CREATE TRIGGER dhcp4_server_AUPD AFTER UPDATE ON dhcp4_server
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP4('dhcp4_server', NEW.id, "update");
    END $$
DELIMITER ;

# Create dhcp4_server delete trigger
DELIMITER $$
CREATE TRIGGER dhcp4_server_ADEL AFTER DELETE ON dhcp4_server
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP4('dhcp4_server', OLD.id, "delete");
    END $$
DELIMITER ;

# Create dhcp6_server insert trigger
DELIMITER $$
CREATE TRIGGER dhcp6_server_AINS AFTER INSERT ON dhcp6_server
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP6('dhcp6_server', NEW.id, "create");
    END $$
DELIMITER ;

# Create dhcp6_server update trigger
DELIMITER $$
CREATE TRIGGER dhcp6_server_AUPD AFTER UPDATE ON dhcp6_server
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP6('dhcp6_server', NEW.id, "update");
    END $$
DELIMITER ;

# Create dhcp6_server delete trigger
DELIMITER $$
CREATE TRIGGER dhcp6_server_ADEL AFTER DELETE ON dhcp6_server
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP6('dhcp6_server', OLD.id, "delete");
    END $$
DELIMITER ;

# Put the auth key in hexadecimal (double size but far more user friendly).
ALTER TABLE hosts
    MODIFY COLUMN auth_key VARCHAR(32) NULL;

# Update the schema version number
UPDATE schema_version
    SET version = '8', minor = '1';

# This line concludes the schema upgrade to version 8.1.

# This line starts the schema upgrade to version 8.2.

# Drop existing trigger on the dhcp4_shared_network table.
DROP TRIGGER dhcp4_shared_network_ADEL;

# Create new trigger which will delete options associated with the shared
# network.
DELIMITER $$
CREATE TRIGGER dhcp4_shared_network_BDEL BEFORE DELETE ON dhcp4_shared_network
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP4('dhcp4_shared_network', OLD.id, "delete");
        DELETE FROM dhcp4_options WHERE shared_network_name = OLD.name;
    END $$
DELIMITER ;

# Drop existing trigger on the dhcp4_subnet table.
DROP TRIGGER dhcp4_subnet_ADEL;

# Create new trigger which will delete pools associated with the subnet and
# the options associated with the subnet.
DELIMITER $$
CREATE TRIGGER dhcp4_subnet_BDEL BEFORE DELETE ON dhcp4_subnet
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP4('dhcp4_subnet', OLD.subnet_id, "delete");
        DELETE FROM dhcp4_pool WHERE subnet_id = OLD.subnet_id;
        DELETE FROM dhcp4_options WHERE dhcp4_subnet_id = OLD.subnet_id;
    END $$
DELIMITER ;

# Do not perform cascade deletion of the data in the dhcp4_pool because
# the cascade deletion does not execute triggers associated with the table.
# Instead we are going to use triggers on the dhcp4_subnet table.
ALTER TABLE dhcp4_pool
    DROP FOREIGN KEY fk_dhcp4_pool_subnet_id;

ALTER TABLE dhcp4_pool
    ADD CONSTRAINT fk_dhcp4_pool_subnet_id FOREIGN KEY (subnet_id)
    REFERENCES dhcp4_subnet (subnet_id)
    ON DELETE NO ACTION ON UPDATE CASCADE;

# Drop existing trigger on the dhcp6_shared_network table.
DROP TRIGGER dhcp6_shared_network_ADEL;

# Create new trigger which will delete options associated with the shared
# network.
DELIMITER $$
CREATE TRIGGER dhcp6_shared_network_BDEL BEFORE DELETE ON dhcp6_shared_network
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP6('dhcp6_shared_network', OLD.id, "delete");
        DELETE FROM dhcp6_options WHERE shared_network_name = OLD.name;
    END $$
DELIMITER ;

# Drop existing trigger on the dhcp6_subnet table.
DROP TRIGGER dhcp6_subnet_ADEL;

# Create new trigger which will delete pools associated with the subnet and
# the options associated with the subnet.
DELIMITER $$
CREATE TRIGGER dhcp6_subnet_BDEL BEFORE DELETE ON dhcp6_subnet
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP6('dhcp6_subnet', OLD.subnet_id, "delete");
        DELETE FROM dhcp6_pool WHERE subnet_id = OLD.subnet_id;
        DELETE FROM dhcp6_pd_pool WHERE subnet_id = OLD.subnet_id;
        DELETE FROM dhcp6_options WHERE dhcp6_subnet_id = OLD.subnet_id;
    END $$
DELIMITER ;

# Do not perform cascade deletion of the data in the dhcp6_pool and dhcp6_pd_pool
# because the cascaded deletion does not execute triggers associated with the table.
# Instead we are going to use triggers on the dhcp6_subnet table.
ALTER TABLE dhcp6_pool
    DROP FOREIGN KEY fk_dhcp6_pool_subnet_id;

ALTER TABLE dhcp6_pd_pool
    DROP FOREIGN KEY fk_dhcp6_pd_pool_subnet_id;

ALTER TABLE dhcp6_pool
    ADD CONSTRAINT fk_dhcp6_pool_subnet_id FOREIGN KEY (subnet_id)
    REFERENCES dhcp6_subnet (subnet_id)
    ON DELETE NO ACTION ON UPDATE CASCADE;

ALTER TABLE dhcp6_pd_pool
    ADD CONSTRAINT fk_dhcp6_pd_pool_subnet_id FOREIGN KEY (subnet_id)
    REFERENCES dhcp6_subnet (subnet_id)
    ON DELETE NO ACTION ON UPDATE CASCADE;

# Create trigger which removes pool specific options upon removal of
# the pool.
DELIMITER $$
CREATE TRIGGER dhcp6_pd_pool_BDEL BEFORE DELETE ON dhcp6_pd_pool FOR EACH ROW
BEGIN
DELETE FROM dhcp6_options WHERE scope_id = 6 AND pd_pool_id = OLD.id;
END
$$
DELIMITER ;

# Add missing columns in pools.
ALTER TABLE dhcp4_pool
    ADD COLUMN client_class VARCHAR(128) DEFAULT NULL,
    ADD COLUMN require_client_classes LONGTEXT,
    ADD COLUMN user_context LONGTEXT;

ALTER TABLE dhcp6_pd_pool
    ADD COLUMN excluded_prefix VARCHAR(45) DEFAULT NULL,
    ADD COLUMN excluded_prefix_length TINYINT(3) NOT NULL,
    ADD COLUMN client_class VARCHAR(128) DEFAULT NULL,
    ADD COLUMN require_client_classes LONGTEXT,
    ADD COLUMN user_context LONGTEXT;

ALTER TABLE dhcp6_pool
    ADD COLUMN client_class VARCHAR(128) DEFAULT NULL,
    ADD COLUMN require_client_classes LONGTEXT,
    ADD COLUMN user_context LONGTEXT;

-- -----------------------------------------------------
--
-- New version of the createOptionAuditDHCP4 stored
-- procedure which updates modification timestamp of
-- a parent object when an option is modified.
--
-- The following parameters are passed to the procedure:
-- - modification_type: "create", "update" or "delete"
-- - scope_id: identifier of the option scope, e.g.
--   global, subnet specific etc.
-- - option_id: identifier of the option.
-- - subnet_id: identifier of the subnet if the option
--   belongs to the subnet.
-- - host_id: identifier of the host if the option
-- - belongs to the host.
-- - network_name: shared network name if the option
--   belongs to the shared network.
-- - pool_id: identifier of the pool if the option
--   belongs to the pool.
-- - modification_ts: modification timestamp of the
--   option.
-- -----------------------------------------------------
DROP PROCEDURE IF EXISTS createOptionAuditDHCP4;
DELIMITER $$
CREATE PROCEDURE createOptionAuditDHCP4(IN modification_type VARCHAR(32),
                                        IN scope_id TINYINT(3) UNSIGNED,
                                        IN option_id BIGINT(20) UNSIGNED,
                                        IN subnet_id INT(10) UNSIGNED,
                                        IN host_id INT(10) UNSIGNED,
                                        IN network_name VARCHAR(128),
                                        IN pool_id BIGINT(20),
                                        IN modification_ts TIMESTAMP)
BEGIN
    # These variables will hold shared network id and subnet id that
    # we will select.
    DECLARE snid VARCHAR(128);
    DECLARE sid INT(10) UNSIGNED;

    # Cascade transaction flag is set to 1 to prevent creation of
    # the audit entries for the options when the options are
    # created as part of the parent object creation or update.
    # For example: when the option is added as part of the subnet
    # addition, the cascade transaction flag is equal to 1. If
    # the option is added into the existing subnet the cascade
    # transaction is equal to 0. Note that depending on the option
    # scope the audit entry will contain the object_type value
    # of the parent object to cause the server to replace the
    # entire subnet. The only case when the object_type will be
    # set to 'dhcp4_options' is when a global option is added.
    # Global options do not have the owner.
    IF @cascade_transaction IS NULL OR @cascade_transaction = 0 THEN
        # todo: host manager hasn't been updated to use audit
        # mechanisms so ignore host specific options for now.
        IF scope_id = 0 THEN
            # If a global option is added or modified, create audit
            # entry for the 'dhcp4_options' table.
            CALL createAuditEntryDHCP4('dhcp4_options', option_id, modification_type);
        ELSEIF scope_id = 1 THEN
            # If subnet specific option is added or modified, update
            # the modification timestamp of this subnet to allow the
            # servers to refresh the subnet information. This will
            # also result in creating an audit entry for this subnet.
            UPDATE dhcp4_subnet AS s SET s.modification_ts = modification_ts
                WHERE s.subnet_id = subnet_id;
        ELSEIF scope_id = 4 THEN
            # If shared network specific option is added or modified,
            # update the modification timestamp of this shared network
            # to allow the servers to refresh the shared network
            # information. This will also result in creating an
            # audit entry for this shared network.
           SELECT id INTO snid FROM dhcp4_shared_network WHERE name = network_name LIMIT 1;
           UPDATE dhcp4_shared_network AS n SET n.modification_ts = modification_ts
                WHERE n.id = snid;
        ELSEIF scope_id = 5 THEN
            # If pool specific option is added or modified, update
            # the modification timestamp of the owning subnet.
            SELECT dhcp4_pool.subnet_id INTO sid FROM dhcp4_pool WHERE id = pool_id;
            UPDATE dhcp4_subnet AS s SET s.modification_ts = modification_ts
                WHERE s.subnet_id = sid;
        END IF;
    END IF;
END $$
DELIMITER ;

# Recreate dhcp4_options_AINS trigger to pass timestamp to the updated
# version of the createOptionAuditDHCP4.
DROP TRIGGER IF EXISTS dhcp4_options_AINS;

# This trigger is executed after inserting a DHCPv4 option into the
# database. It creates appropriate audit entry for this option or
# a parent object owning this option.
DELIMITER $$
CREATE TRIGGER dhcp4_options_AINS AFTER INSERT ON dhcp4_options
    FOR EACH ROW
    BEGIN
        CALL createOptionAuditDHCP4("create", NEW.scope_id, NEW.option_id, NEW.dhcp4_subnet_id,
                                    NEW.host_id, NEW.shared_network_name, NEW.pool_id,
                                    NEW.modification_ts);
    END $$
DELIMITER ;

# Recreate dhcp4_options_AUPD trigger to pass timestamp to the updated
# version of the createOptionAuditDHCP4.
DROP TRIGGER IF EXISTS dhcp4_options_AUPD;

# This trigger is executed after updating a DHCPv4 option in the
# database. It creates appropriate audit entry for this option or
# a parent object owning this option.
DELIMITER $$
CREATE TRIGGER dhcp4_options_AUPD AFTER UPDATE ON dhcp4_options
    FOR EACH ROW
    BEGIN
        CALL createOptionAuditDHCP4("update", NEW.scope_id, NEW.option_id, NEW.dhcp4_subnet_id,
                                    NEW.host_id, NEW.shared_network_name, NEW.pool_id,
                                    NEW.modification_ts);
    END $$
DELIMITER ;

# Recreate dhcp4_options_ADEL trigger to pass timestamp to the updated
# version of the createOptionAuditDHCP4.
DROP TRIGGER IF EXISTS dhcp4_options_ADEL;

# This trigger is executed after deleting a DHCPv4 option in the
# database. It creates appropriate audit entry for this option or
# a parent object owning this option.
DELIMITER $$
CREATE TRIGGER dhcp4_options_ADEL AFTER DELETE ON dhcp4_options
    FOR EACH ROW
    BEGIN
        CALL createOptionAuditDHCP4("delete", OLD.scope_id, OLD.option_id, OLD.dhcp4_subnet_id,
                                    OLD.host_id, OLD.shared_network_name, OLD.pool_id,
                                    NOW());
    END $$
DELIMITER ;

-- -----------------------------------------------------
--
-- New version of the createOptionAuditDHCP4 stored
-- procedure which updates modification timestamp of
-- a parent object when an option is modified.
--
-- The following parameters are passed to the procedure:
-- - modification_type: "create", "update" or "delete"
-- - scope_id: identifier of the option scope, e.g.
--   global, subnet specific etc. See dhcp_option_scope
--   for specific values.
-- - option_id: identifier of the option.
-- - subnet_id: identifier of the subnet if the option
--   belongs to the subnet.
-- - host_id: identifier of the host if the option
-- - belongs to the host.
-- - network_name: shared network name if the option
--   belongs to the shared network.
-- - pool_id: identifier of the pool if the option
--   belongs to the pool.
-- - pd_pool_id: identifier of the pool if the option
--   belongs to the pd pool.
-- - modification_ts: modification timestamp of the
--   option.
-- -----------------------------------------------------
DROP PROCEDURE IF EXISTS createOptionAuditDHCP6;
DELIMITER $$
CREATE PROCEDURE createOptionAuditDHCP6(IN modification_type VARCHAR(32),
                                        IN scope_id TINYINT(3) UNSIGNED,
                                        IN option_id BIGINT(20) UNSIGNED,
                                        IN subnet_id INT(10) UNSIGNED,
                                        IN host_id INT(10) UNSIGNED,
                                        IN network_name VARCHAR(128),
                                        IN pool_id BIGINT(20),
                                        IN pd_pool_id BIGINT(20),
                                        IN modification_ts TIMESTAMP)
BEGIN
    # These variables will hold shared network id and subnet id that
    # we will select.
    DECLARE snid VARCHAR(128);
    DECLARE sid INT(10) UNSIGNED;

    # Cascade transaction flag is set to 1 to prevent creation of
    # the audit entries for the options when the options are
    # created as part of the parent object creation or update.
    # For example: when the option is added as part of the subnet
    # addition, the cascade transaction flag is equal to 1. If
    # the option is added into the existing subnet the cascade
    # transaction is equal to 0. Note that depending on the option
    # scope the audit entry will contain the object_type value
    # of the parent object to cause the server to replace the
    # entire subnet. The only case when the object_type will be
    # set to 'dhcp6_options' is when a global option is added.
    # Global options do not have the owner.
    IF @cascade_transaction IS NULL OR @cascade_transaction = 0 THEN
        # todo: host manager hasn't been updated to use audit
        # mechanisms so ignore host specific options for now.
        IF scope_id = 0 THEN
            # If a global option is added or modified, create audit
            # entry for the 'dhcp6_options' table.
            CALL createAuditEntryDHCP6('dhcp6_options', option_id, modification_type);
        ELSEIF scope_id = 1 THEN
            # If subnet specific option is added or modified, update
            # the modification timestamp of this subnet to allow the
            # servers to refresh the subnet information. This will
            # also result in creating an audit entry for this subnet.
            UPDATE dhcp6_subnet AS s SET s.modification_ts = modification_ts
                WHERE s.subnet_id = subnet_id;
        ELSEIF scope_id = 4 THEN
            # If shared network specific option is added or modified,
            # update the modification timestamp of this shared network
            # to allow the servers to refresh the shared network
            # information. This will also result in creating an
            # audit entry for this shared network.
           SELECT id INTO snid FROM dhcp6_shared_network WHERE name = network_name LIMIT 1;
           UPDATE dhcp6_shared_network AS n SET n.modification_ts = modification_ts
               WHERE n.id = snid;
        ELSEIF scope_id = 5 THEN
            # If pool specific option is added or modified, update
            # the modification timestamp of the owning subnet.
            SELECT dhcp6_pool.subnet_id INTO sid FROM dhcp6_pool WHERE id = pool_id;
            UPDATE dhcp6_subnet AS s SET s.modification_ts = modification_ts
                WHERE s.subnet_id = sid;
        ELSEIF scope_id = 6 THEN
            # If pd pool specific option is added or modified, create
            # audit entry for the subnet which this pool belongs to.
            SELECT dhcp6_pd_pool.subnet_id INTO sid FROM dhcp6_pd_pool WHERE id = pd_pool_id;
            UPDATE dhcp6_subnet AS s SET s.modification_ts = modification_ts
                WHERE s.subnet_id = sid;
        END IF;
    END IF;
END $$
DELIMITER ;

# Recreate dhcp6_options_AINS trigger to pass timestamp to the updated
# version of the createOptionAuditDHCP6.
DROP TRIGGER IF EXISTS dhcp6_options_AINS;

# This trigger is executed after inserting a DHCPv6 option into the
# database. It creates appropriate audit entry for this option or
# a parent object owning this option.
DELIMITER $$
CREATE TRIGGER dhcp6_options_AINS AFTER INSERT ON dhcp6_options
    FOR EACH ROW
    BEGIN
        CALL createOptionAuditDHCP6("create", NEW.scope_id, NEW.option_id, NEW.dhcp6_subnet_id,
                                    NEW.host_id, NEW.shared_network_name, NEW.pool_id,
                                    NEW.pd_pool_id, NEW.modification_ts);
    END $$
DELIMITER ;

# Recreate dhcp6_options_AUPD trigger to pass timestamp to the updated
# version of the createOptionAuditDHCP6.
DROP TRIGGER IF EXISTS dhcp6_options_AUPD;

# This trigger is executed after updating a DHCPv6 option in the
# database. It creates appropriate audit entry for this option or
# a parent object owning this option.
DELIMITER $$
CREATE TRIGGER dhcp6_options_AUPD AFTER UPDATE ON dhcp6_options
    FOR EACH ROW
    BEGIN
        CALL createOptionAuditDHCP6("update", NEW.scope_id, NEW.option_id, NEW.dhcp6_subnet_id,
                                    NEW.host_id, NEW.shared_network_name, NEW.pool_id,
                                    NEW.pd_pool_id, NEW.modification_ts);
    END $$
DELIMITER ;

# Recreate dhcp6_options_ADEL trigger to pass timestamp to the updated
# version of the createOptionAuditDHCP6.
DROP TRIGGER IF EXISTS dhcp6_options_ADEL;

# This trigger is executed after deleting a DHCPv6 option in the
# database. It creates appropriate audit entry for this option or
# a parent object owning this option.
DELIMITER $$
CREATE TRIGGER dhcp6_options_ADEL AFTER DELETE ON dhcp6_options
    FOR EACH ROW
    BEGIN
        CALL createOptionAuditDHCP6("delete", OLD.scope_id, OLD.option_id, OLD.dhcp6_subnet_id,
                                    OLD.host_id, OLD.shared_network_name, OLD.pool_id,
                                    OLD.pd_pool_id, NOW());
    END $$
DELIMITER ;

# Update the schema version number
UPDATE schema_version
    SET version = '8', minor = '2';

# This line concludes the schema upgrade to version 8.2.

# This line starts the schema upgrade to version 9.0.

# Create hostname index for host reservations
CREATE INDEX hosts_by_hostname ON hosts (hostname);

# Create hostname index for lease4
CREATE INDEX lease4_by_hostname ON lease4 (hostname);

# Create hostname index for lease6
CREATE INDEX lease6_by_hostname ON lease6 (hostname);

# Update the schema version number
UPDATE schema_version
    SET version = '9', minor = '0';

# This line concludes the schema upgrade to version 9.0.

# This line starts the schema upgrade to version 9.1.

# Add new DDNS related columns to shared networks and subnets
ALTER TABLE dhcp4_shared_network
    ADD COLUMN ddns_send_updates TINYINT(1) DEFAULT NULL,
    ADD COLUMN ddns_override_no_update TINYINT(1) DEFAULT NULL,
    ADD COLUMN ddns_override_client_update TINYINT(1) DEFAULT NULL,
    ADD COLUMN ddns_replace_client_name TINYINT(3) DEFAULT NULL,
    ADD COLUMN ddns_generated_prefix VARCHAR(255) DEFAULT NULL,
    ADD COLUMN ddns_qualifying_suffix VARCHAR(255) DEFAULT NULL;

ALTER TABLE dhcp6_shared_network
    ADD COLUMN ddns_send_updates TINYINT(1) DEFAULT NULL,
    ADD COLUMN ddns_override_no_update TINYINT(1) DEFAULT NULL,
    ADD COLUMN ddns_override_client_update TINYINT(1) DEFAULT NULL,
    ADD COLUMN ddns_replace_client_name TINYINT(3) DEFAULT NULL,
    ADD COLUMN ddns_generated_prefix VARCHAR(255) DEFAULT NULL,
    ADD COLUMN ddns_qualifying_suffix VARCHAR(255) DEFAULT NULL;

ALTER TABLE dhcp4_subnet
    ADD COLUMN ddns_send_updates TINYINT(1) DEFAULT NULL,
    ADD COLUMN ddns_override_no_update TINYINT(1) DEFAULT NULL,
    ADD COLUMN ddns_override_client_update TINYINT(1) DEFAULT NULL,
    ADD COLUMN ddns_replace_client_name TINYINT(3) DEFAULT NULL,
    ADD COLUMN ddns_generated_prefix VARCHAR(255) DEFAULT NULL,
    ADD COLUMN ddns_qualifying_suffix VARCHAR(255) DEFAULT NULL;

ALTER TABLE dhcp6_subnet
    ADD COLUMN ddns_send_updates TINYINT(1) DEFAULT NULL,
    ADD COLUMN ddns_override_no_update TINYINT(1) DEFAULT NULL,
    ADD COLUMN ddns_override_client_update TINYINT(1) DEFAULT NULL,
    ADD COLUMN ddns_replace_client_name TINYINT(3) DEFAULT NULL,
    ADD COLUMN ddns_generated_prefix VARCHAR(255) DEFAULT NULL,
    ADD COLUMN ddns_qualifying_suffix VARCHAR(255) DEFAULT NULL;

# Update the schema version number
UPDATE schema_version
    SET version = '9', minor = '1';

# This line concludes the schema upgrade to version 9.1.

# This line starts the schema upgrade to version 9.2.

# Add missing indexes (foreign keys) to the dhcp4_options table.
ALTER TABLE dhcp4_options ADD CONSTRAINT fk_dhcp4_options_shared_network
    FOREIGN KEY (shared_network_name)
        REFERENCES dhcp4_shared_network(name)
        ON DELETE CASCADE ON UPDATE CASCADE;

ALTER TABLE dhcp4_options ADD CONSTRAINT fk_dhcp4_options_subnet
    FOREIGN KEY (dhcp4_subnet_id)
        REFERENCES dhcp4_subnet(subnet_id)
        ON DELETE CASCADE ON UPDATE CASCADE;

ALTER TABLE dhcp4_options ADD CONSTRAINT fk_dhcp4_options_pool
    FOREIGN KEY (pool_id)
        REFERENCES dhcp4_pool(id)
        ON DELETE CASCADE ON UPDATE CASCADE;

# Add missing indexes (foreign keys) to the dhcp6_options table.
ALTER TABLE dhcp6_options ADD CONSTRAINT fk_dhcp6_options_shared_network
    FOREIGN KEY (shared_network_name)
        REFERENCES dhcp6_shared_network(name)
        ON DELETE CASCADE ON UPDATE CASCADE;

ALTER TABLE dhcp6_options ADD CONSTRAINT fk_dhcp6_options_subnet
    FOREIGN KEY (dhcp6_subnet_id)
        REFERENCES dhcp6_subnet(subnet_id)
        ON DELETE CASCADE ON UPDATE CASCADE;

ALTER TABLE dhcp6_options ADD CONSTRAINT fk_dhcp6_options_pool
    FOREIGN KEY (pool_id)
        REFERENCES dhcp6_pool(id)
        ON DELETE CASCADE ON UPDATE CASCADE;

ALTER TABLE dhcp6_options ADD CONSTRAINT fk_dhcp6_options_pd_pool
    FOREIGN KEY (pd_pool_id)
        REFERENCES dhcp6_pd_pool(id)
        ON DELETE CASCADE ON UPDATE CASCADE;

# Update the schema version number
UPDATE schema_version
    SET version = '9', minor = '2';

# This line concludes the schema upgrade to version 9.2.

# This line starts the schema upgrade to version 9.3.

# Fix stat_lease4_update trigger
DROP TRIGGER stat_lease4_update;

DELIMITER $$
CREATE TRIGGER stat_lease4_update AFTER UPDATE ON lease4
    FOR EACH ROW
    BEGIN
        IF OLD.subnet_id != NEW.subnet_id OR OLD.state != NEW.state THEN
            IF OLD.state = 0 OR OLD.state = 1 THEN
                # Decrement the old state count if record exists
                UPDATE lease4_stat
                SET leases = IF(leases > 0, leases - 1, 0)
                WHERE subnet_id = OLD.subnet_id AND state = OLD.state;
            END IF;

            IF NEW.state = 0 OR NEW.state = 1 THEN
                # Increment the new state count if record exists
                UPDATE lease4_stat SET leases = leases + 1
                WHERE subnet_id = NEW.subnet_id AND state = NEW.state;

                # Insert new state record if it does not exist
                IF ROW_COUNT() <= 0 THEN
                    INSERT INTO lease4_stat VALUES (NEW.subnet_id, NEW.state, 1);
                END IF;
            END IF;
        END IF;
    END $$
DELIMITER ;

# Fix stat_lease4_delete trigger
DROP TRIGGER stat_lease4_delete;

DELIMITER $$
CREATE TRIGGER stat_lease4_delete AFTER DELETE ON lease4
    FOR EACH ROW
    BEGIN
        IF OLD.state = 0 OR OLD.state = 1 THEN
            # Decrement the state count if record exists
            UPDATE lease4_stat
            SET leases = IF(leases > 0, leases - 1, 0)
            WHERE subnet_id = OLD.subnet_id AND OLD.state = state;
        END IF;
    END $$
DELIMITER ;

# Fix stat_lease6_update trigger
DROP TRIGGER stat_lease6_update;

DELIMITER $$
CREATE TRIGGER stat_lease6_update AFTER UPDATE ON lease6
    FOR EACH ROW
    BEGIN
        IF OLD.subnet_id != NEW.subnet_id OR
           OLD.lease_type != NEW.lease_type OR
           OLD.state != NEW.state THEN
            IF OLD.state = 0 OR OLD.state = 1 THEN
                # Decrement the old state count if record exists
                UPDATE lease6_stat
                SET leases = IF(leases > 0, leases - 1, 0)
                WHERE subnet_id = OLD.subnet_id AND lease_type = OLD.lease_type
                AND state = OLD.state;
            END IF;

            IF NEW.state = 0 OR NEW.state = 1 THEN
                # Increment the new state count if record exists
                UPDATE lease6_stat SET leases = leases + 1
                WHERE subnet_id = NEW.subnet_id AND lease_type = NEW.lease_type
                AND state = NEW.state;

                # Insert new state record if it does not exist
                IF ROW_COUNT() <= 0 THEN
                    INSERT INTO lease6_stat
                    VALUES (NEW.subnet_id, NEW.lease_type, NEW.state, 1);
                END IF;
            END IF;
        END IF;
    END $$
DELIMITER ;

# Fix stat_lease6_delete trigger
DROP TRIGGER stat_lease6_delete;

DELIMITER $$
CREATE TRIGGER stat_lease6_delete AFTER DELETE ON lease6
    FOR EACH ROW
    BEGIN
        IF OLD.state = 0 OR OLD.state = 1 THEN
            # Decrement the state count if record exists
            UPDATE lease6_stat
            SET leases = IF(leases > 0, leases - 1, 0)
            WHERE subnet_id = OLD.subnet_id AND lease_type = OLD.lease_type
            AND state = OLD.state;
        END IF;
    END $$
DELIMITER ;

# Update the schema version number
UPDATE schema_version
    SET version = '9', minor = '3';

# This line concludes the schema upgrade to version 9.3.

# This line starts the schema upgrade to version 9.4.

# Starting from this version we allow specifying multiple IP reservations
# for the same address in certain DHCP configurations. The server may check
# uniqueness of the IP addresses on its own. This is no longer checked at
# the database level to facilitate the use cases when a single host may
# get the same reserved IP address via different interfaces.

# Replace the unique index with non-unique index so the queries for
# hosts by IPv4 address are still efficient.
DROP INDEX key_dhcp4_ipv4_address_subnet_id ON hosts;
CREATE INDEX key_dhcp4_ipv4_address_subnet_id_identifier
    ON hosts (ipv4_address ASC, dhcp4_subnet_id ASC);

# Replace the unique index with non-unique index so the queries for
# hosts by IPv6 address are still efficient.
DROP INDEX key_dhcp6_address_prefix_len ON ipv6_reservations;
CREATE INDEX key_dhcp6_address_prefix_len
    ON ipv6_reservations (address ASC, prefix_len ASC);

# Stop using a trigger to delete entries dependent on hosts table.
# Use cascade action instead. This works better with complex delete
# statements.
DROP TRIGGER IF EXISTS host_BDEL;

# Replace existing constraint to set cascade actions.
ALTER TABLE ipv6_reservations DROP FOREIGN KEY fk_ipv6_reservations_Host;
ALTER TABLE ipv6_reservations ADD CONSTRAINT fk_ipv6_reservations_Host
    FOREIGN KEY (host_id)
        REFERENCES hosts(host_id)
        ON DELETE CASCADE ON UPDATE CASCADE;

ALTER TABLE dhcp4_options ADD CONSTRAINT fk_dhcp4_options_Host
    FOREIGN KEY (host_id)
        REFERENCES hosts(host_id)
        ON DELETE CASCADE ON UPDATE CASCADE;

ALTER TABLE dhcp6_options ADD CONSTRAINT fk_dhcp6_options_Host
    FOREIGN KEY (host_id)
        REFERENCES hosts(host_id)
        ON DELETE CASCADE ON UPDATE CASCADE;

# Update the schema version number
UPDATE schema_version
    SET version = '9', minor = '4';

# This line concludes the schema upgrade to version 9.4.

# This line starts the schema upgrade to version 9.5.

# Add new reservations flags.
ALTER TABLE dhcp4_subnet
    ADD COLUMN reservations_global BOOL DEFAULT NULL,
    ADD COLUMN reservations_in_subnet BOOL DEFAULT NULL,
    ADD COLUMN reservations_out_of_pool BOOL DEFAULT NULL;

ALTER TABLE dhcp4_shared_network
    ADD COLUMN reservations_global BOOL DEFAULT NULL,
    ADD COLUMN reservations_in_subnet BOOL DEFAULT NULL,
    ADD COLUMN reservations_out_of_pool BOOL DEFAULT NULL;

ALTER TABLE dhcp6_subnet
    ADD COLUMN reservations_global BOOL DEFAULT NULL,
    ADD COLUMN reservations_in_subnet BOOL DEFAULT NULL,
    ADD COLUMN reservations_out_of_pool BOOL DEFAULT NULL;

ALTER TABLE dhcp6_shared_network
    ADD COLUMN reservations_global BOOL DEFAULT NULL,
    ADD COLUMN reservations_in_subnet BOOL DEFAULT NULL,
    ADD COLUMN reservations_out_of_pool BOOL DEFAULT NULL;

# DROP reservation_mode
ALTER TABLE dhcp4_subnet DROP COLUMN reservation_mode;
ALTER TABLE dhcp4_shared_network DROP COLUMN reservation_mode;
ALTER TABLE dhcp6_subnet DROP COLUMN reservation_mode;
ALTER TABLE dhcp6_shared_network DROP COLUMN reservation_mode;

# Update the schema version number
UPDATE schema_version
    SET version = '9', minor = '5';

# This line concludes the schema upgrade to version 9.5.

# This line starts the schema upgrade to version 9.6.

# Add new lease cache parameters.
ALTER TABLE dhcp4_subnet
    ADD COLUMN cache_threshold FLOAT DEFAULT NULL,
    ADD COLUMN cache_max_age INT(10) DEFAULT NULL;

ALTER TABLE dhcp4_shared_network
    ADD COLUMN cache_threshold FLOAT DEFAULT NULL,
    ADD COLUMN cache_max_age INT(10) DEFAULT NULL;

ALTER TABLE dhcp6_subnet
    ADD COLUMN cache_threshold FLOAT DEFAULT NULL,
    ADD COLUMN cache_max_age INT(10) DEFAULT NULL;

ALTER TABLE dhcp6_shared_network
    ADD COLUMN cache_threshold FLOAT DEFAULT NULL,
    ADD COLUMN cache_max_age INT(10) DEFAULT NULL;

# Add an auto-increment ID as primary key to support Percona.
ALTER TABLE logs
    ADD id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY;

# Update the schema version number
UPDATE schema_version
    SET version = '9', minor = '6';

# This line concludes the schema upgrade to version 9.6.

# This line starts the schema upgrade to version 10.

-- -----------------------------------------------------------------------
-- Create a table holding the DHCPv4 client classes. Most table
-- columns map directly to respective client class properties in
-- Kea configuration. The depend_on_known_directly column is
-- explicitly set in an insert or update statement to indicate
-- if the client class directly depends on KNOWN or UNKNOWN
-- built-in classes. A caller should determine it by evaluating
-- a test expression before inserting or updating the client
-- class in the database. The nullable follow_class_name column
-- can be used for positioning the inserted or updated client
-- class within the class hierarchy. Set this column value to
-- an existing class name, after which this class should be
-- placed in the class hierarchy. See dhcp4_client_class_order
-- description for the details of how classes are ordered.
-- -----------------------------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp4_client_class (
    id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
    name VARCHAR(128) NOT NULL,
    test TEXT,
    next_server INT UNSIGNED DEFAULT NULL,
    server_hostname VARCHAR(128) DEFAULT NULL,
    boot_file_name VARCHAR(512) DEFAULT NULL,
    only_if_required TINYINT NOT NULL DEFAULT '0',
    valid_lifetime INT DEFAULT NULL,
    min_valid_lifetime INT DEFAULT NULL,
    max_valid_lifetime INT DEFAULT NULL,
    depend_on_known_directly TINYINT NOT NULL DEFAULT '0',
    follow_class_name VARCHAR(128) DEFAULT NULL,
    modification_ts TIMESTAMP NOT NULL,
    PRIMARY KEY (id),
    UNIQUE KEY id_UNIQUE (id),
    UNIQUE KEY name_UNIQUE (name),
    KEY key_dhcp4_client_class_modification_ts (modification_ts)
) ENGINE=InnoDB;

-- -----------------------------------------------------------------------
-- Create a table for ordering client classes and holding information
-- about indirect dependencies on KNOWN/UKNOWN built-in client classes.
-- Each class in the dhcp4_client_class table has a corresponding row
-- in the dhcp4_client_class_order table. A caller should not modify
-- the contents of this table. Its entries are automatically created
-- upon inserting or updating client classes in the dhcp4_client_classes
-- using triggers. The order_index designates the position of the client
-- class within the class hierarchy. If the follow_class_name value of
-- the dhcp4_client_class table is set to NULL, the client class is
-- appended at the end of the hierarchy. The assigned order_index
-- value for that class is set to a maximum current value + 1.
-- If the follow_client_class specifies a name of an existing class,
-- the generated order_index is set to an id of that class + 1, and
-- the order_index values of the later classes are incremented by 1.
-- The depend_on_known_indirectly column holds a boolean value indicating
-- whether the given class depends on KNOWN/UKNOWN built-in classes
-- via other classes, i.e. it depends on classes that directly or
-- indirectly depend on these built-ins. This value is auto-generated
-- by a trigger on the dhcp4_client_class_dependency table.
-- -----------------------------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp4_client_class_order (
    class_id BIGINT UNSIGNED NOT NULL,
    order_index BIGINT UNSIGNED NOT NULL,
    depend_on_known_indirectly TINYINT NOT NULL DEFAULT '0',
    PRIMARY KEY (class_id),
    KEY key_dhcp4_client_class_order_index (order_index),
    CONSTRAINT fk_dhcp4_client_class_order_class_id FOREIGN KEY (class_id)
        REFERENCES dhcp4_client_class (id) ON DELETE CASCADE
) ENGINE=InnoDB;

DROP TRIGGER IF EXISTS dhcp4_client_class_AINS;
DROP TRIGGER IF EXISTS dhcp4_client_class_AUPD;
DROP TRIGGER IF EXISTS dhcp4_client_class_ADEL;
DROP PROCEDURE IF EXISTS setClientClass4Order;

-- -----------------------------------------------------------------------
-- Stored procedure positioning an inserted or updated client class
-- within the class hierarchy, depending on the value of the
-- follow_class_name parameter.
--
-- Parameters:
-- - id id of the positioned class,
-- - follow_class_name name of the class after which this class should be
--   positioned within the class hierarchy.
-- - old_follow_class_name previous name of the class after which this
--   class was positioned within the class hierarchy.
-- -----------------------------------------------------------------------
DELIMITER $$
CREATE PROCEDURE setClientClass4Order(IN id BIGINT UNSIGNED,
                                      IN follow_class_name VARCHAR(128),
                                      IN old_follow_class_name VARCHAR(128))
proc_label:BEGIN
    -- This variable will be optionally set if the follow_class_name
    -- column value is specified.
    DECLARE follow_class_index BIGINT UNSIGNED;
    DECLARE msg TEXT;

    -- Remember currently used value of depend_on_known_indirectly.
    SET @depend_on_known_indirectly = (
        SELECT depend_on_known_indirectly FROM dhcp4_client_class_order WHERE id = class_id
    );

    -- Bail if the class is updated without re-positioning.
    IF(
        @depend_on_known_indirectly IS NOT NULL AND
        ((follow_class_name IS NULL AND old_follow_class_name IS NULL) OR
         (follow_class_name = old_follow_class_name))
    ) THEN
        -- The depend_on_known_indirectly is set to 0 because this procedure is invoked
        -- whenever the dhcp4_client_class record is updated. Such update may include
        -- test expression changes impacting the dependency on KNOWN/UNKNOWN classes.
        -- This value will be later adjusted when dependencies are inserted.
        UPDATE dhcp4_client_class_order SET depend_on_known_indirectly = 0
            WHERE class_id = id;
        LEAVE proc_label;
    END IF;

    IF follow_class_name IS NOT NULL THEN
        -- Get the position of the class after which the new class should be added.
        SET follow_class_index = (
            SELECT o.order_index FROM dhcp4_client_class AS c
                INNER JOIN dhcp4_client_class_order AS o
                    ON c.id = o.class_id
            WHERE c.name = follow_class_name
        );
        IF follow_class_index IS NULL THEN
            -- The class with a name specified with follow_class_name does
            -- not exist.
            SET msg = CONCAT('Class ', follow_class_name, ' does not exist.');
            SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = msg;
        END IF;
        -- We need to place the new class at the position of follow_class_index + 1.
        -- There may be a class at this position already.
        IF EXISTS(SELECT * FROM dhcp4_client_class_order WHERE order_index = follow_class_index + 1) THEN
            -- There is a class at this position already. Let's move all classes
            -- starting from this position by one to create a spot for the new
            -- class.
            UPDATE dhcp4_client_class_order
                SET order_index = order_index + 1
            WHERE order_index >= follow_class_index + 1
            ORDER BY order_index DESC;
        END IF;
    ELSE
        -- A caller did not specify the follow_class_name value. Let's append the
        -- new class at the end of the hierarchy.
        SET follow_class_index = (SELECT MAX(order_index) FROM dhcp4_client_class_order);
        IF follow_class_index IS NULL THEN
            -- Apparently, there are no classes. Let's start from 0.
            SET follow_class_index = 0;
        END IF;
    END IF;

    -- Check if moving the class doesn't break dependent classes.
    IF EXISTS(
        SELECT 1 FROM dhcp4_client_class_dependency AS d
            INNER JOIN dhcp4_client_class_order AS o
                ON d.class_id = o.class_id
            WHERE d.dependency_id = id AND o.order_index < follow_class_index + 1
        LIMIT 1
    ) THEN
        SET msg = CONCAT('Unable to move class with id ', id, ' because it would break its dependencies');
        SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = msg;
    END IF;

    -- The depend_on_known_indirectly is set to 0 because this procedure is invoked
    -- whenever the dhcp4_client_class record is updated. Such update may include
    -- test expression changes impacting the dependency on KNOWN/UNKNOWN classes.
    -- This value will be later adjusted when dependencies are inserted.
    REPLACE INTO dhcp4_client_class_order(class_id, order_index, depend_on_known_indirectly)
        VALUES (id, follow_class_index + 1, 0);
END $$
DELIMITER ;

-- -----------------------------------------------------------------------
-- Trigger to position an inserted class within the class hierarchy
-- and create audit.
-- -----------------------------------------------------------------------
DELIMITER $$
CREATE TRIGGER dhcp4_client_class_AINS AFTER INSERT ON dhcp4_client_class FOR EACH ROW BEGIN
    CALL setClientClass4Order(NEW.id, NEW.follow_class_name, NULL);
    CALL createAuditEntryDHCP4('dhcp4_client_class', NEW.id, "create");
END $$
DELIMITER ;

-- -----------------------------------------------------------------------
-- Trigger to position an updated class within the class hierarchy,
-- create audit and remember the direct dependency on the
-- KNOWN/UNKNOWN built-in classes before the class update.
-- When updating a client class, it is very important to ensure that
-- its dependency on KNOWN or UNKNOWN built-in client classes is not
-- changed. It is because there may be other classes that depend on
-- these built-ins via this class. Changing the dependency would break
-- the chain of dependencies for other classes. Here, we store the
-- information about the dependency in the session variables. Their
-- values will be compared with the new dependencies after an update.
-- If they change, an error will be signaled.
-- -----------------------------------------------------------------------
DELIMITER $$
CREATE TRIGGER dhcp4_client_class_AUPD AFTER UPDATE ON dhcp4_client_class FOR EACH ROW BEGIN
    SET @depend_on_known_directly = OLD.depend_on_known_directly;
    SET @client_class_id = NEW.id;
    CALL setClientClass4Order(NEW.id, NEW.follow_class_name, OLD.follow_class_name);
    CALL createAuditEntryDHCP4('dhcp4_client_class', NEW.id, "update");
END $$
DELIMITER ;

-- -----------------------------------------------------------------------
-- Trigger to create dhcp4_client_class audit.
-- -----------------------------------------------------------------------
DELIMITER $$
CREATE TRIGGER dhcp4_client_class_ADEL AFTER DELETE ON dhcp4_client_class FOR EACH ROW BEGIN
    CALL createAuditEntryDHCP4('dhcp4_client_class', OLD.id, "delete");
END $$
DELIMITER ;

-- -----------------------------------------------------------------------
-- Create a table associating client classes stored in the
-- dhcp4_client_class table with their dependencies. There is
-- an M:N relationship between these tables. Each class may have
-- many dependencies (created using member operator in test expression),
-- and each class may be a dependency for many other classes. A caller
-- is responsible for inserting dependencies for a class after inserting
-- or updating it in the dhcp4_client_class table. A caller should
-- delete all existing dependencies for an updated client class, evaluate
-- test expression to discover new dependencies (in case test expression
-- has changed), and insert new dependencies to this table.
-- -----------------------------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp4_client_class_dependency (
    class_id BIGINT UNSIGNED NOT NULL,
    dependency_id BIGINT UNSIGNED NOT NULL,
    PRIMARY KEY (class_id,dependency_id),
    KEY dhcp4_client_class_dependency_id_idx (dependency_id),
    CONSTRAINT dhcp4_client_class_class_id FOREIGN KEY (class_id)
        REFERENCES dhcp4_client_class (id) ON DELETE CASCADE,
    CONSTRAINT dhcp4_client_class_dependency_id FOREIGN KEY (dependency_id)
        REFERENCES dhcp4_client_class (id)
) ENGINE=InnoDB;

DROP TRIGGER IF EXISTS dhcp4_client_class_dependency_BINS;
DROP PROCEDURE IF EXISTS checkDHCPv4ClientClassDependency;

-- -----------------------------------------------------------------------
-- Stored procedure verifying if class dependency is met. It includes
-- checking if referenced classes exist, are associated with the same
-- server or all servers, and are defined before the class specified with
-- class_id.
--
-- Parameters:
-- - class_id id client class,
-- - dependency_id id of the dependency.
-- -----------------------------------------------------------------------
DELIMITER $$
CREATE PROCEDURE checkDHCPv4ClientClassDependency(IN class_id BIGINT UNSIGNED,
                                                  IN dependency_id BIGINT UNSIGNED)
BEGIN
    DECLARE class_index BIGINT UNSIGNED;
    DECLARE dependency_index BIGINT UNSIGNED;
    DECLARE err_msg TEXT;

    -- We could check the same with a constraint but later in this
    -- trigger we use this value to verify if the dependencies are
    -- met.
    IF class_id IS NULL THEN
        SIGNAL SQLSTATE '45000'
            SET MESSAGE_TEXT = 'Client class id must not be NULL.';
    END IF;
    IF dependency_id IS NULL THEN
        SIGNAL SQLSTATE '45000'
            SET MESSAGE_TEXT = 'Class dependency id must not be NULL.';
    END IF;
    -- Dependencies on self make no sense.
    IF class_id = dependency_id THEN
        SIGNAL SQLSTATE '45000'
            SET MESSAGE_TEXT = 'Client class must not have dependency on self.';
    END IF;
    -- Check position of our class in the hierarchy.
    SET class_index = (
        SELECT o.order_index FROM dhcp4_client_class AS c
            INNER JOIN dhcp4_client_class_order AS o
                ON c.id = o.class_id
        WHERE c.id = class_id);
    IF class_index IS NULL THEN
        SET err_msg = CONCAT('Client class with id ', class_id, ' does not exist.');
        SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = err_msg;
    END IF;
    -- Check position of the dependency.
    SET dependency_index = (
        SELECT o.order_index FROM dhcp4_client_class AS c
            INNER JOIN dhcp4_client_class_order AS o ON c.id = o.class_id
        WHERE c.id = dependency_id
    );
    IF dependency_index IS NULL THEN
        SET err_msg = CONCAT('Client class with id ', dependency_id, ' does not exist.');
        SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = err_msg;
    END IF;
    -- The dependency must not be later than our class.
    IF dependency_index > class_index THEN
        SET err_msg = CONCAT('Client class with id ', class_id, ' must not depend on class defined later with id ', dependency_id);
        SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = err_msg;
    END IF;

    -- Check if all servers associated with the new class have dependent
    -- classes configured. This catches the cases that class A belongs to
    -- server1 and depends on class B which belongs only to server 2.
    -- It is fine if the class B belongs to all servers in this case.
    -- Make a SELECT on the dhcp4_client_class_server table to gather
    -- all servers to which the class belongs. LEFT JOIN it with the
    -- same table, selecting all records matching the dependency class
    -- and the servers to which the new class belongs. If there are
    -- any NULL records joined it implies that some dependencies are
    -- not met (didn't find a dependency for at least one server).
    IF EXISTS(
        SELECT 1 FROM dhcp4_client_class_server AS t1
            LEFT JOIN dhcp4_client_class_server AS t2
                ON t2.class_id = dependency_id AND (t2.server_id = 1 OR t2.server_id = t1.server_id)
        WHERE t1.class_id = class_id AND t2.server_id IS NULL
        LIMIT 1
    ) THEN
        SET err_msg = CONCAT('Unmet dependencies for client class with id ', class_id);
        SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = err_msg;
    END IF;
END $$
DELIMITER ;

-- -----------------------------------------------------------------------
-- Trigger verifying if class dependency is met. It includes checking
-- if referenced classes exist, are associated with the same server
-- or all servers, and are defined before the class specified with
-- class_id.
-- -----------------------------------------------------------------------
DELIMITER $$
CREATE TRIGGER dhcp4_client_class_check_dependency_BINS BEFORE INSERT ON dhcp4_client_class_dependency FOR EACH ROW
BEGIN
    CALL checkDHCPv4ClientClassDependency(NEW.class_id, NEW.dependency_id);
END $$
DELIMITER ;

DROP TRIGGER IF EXISTS dhcp4_client_class_dependency_AINS;
DROP PROCEDURE IF EXISTS updateDHCPv4ClientClassKnownDependency;

-- -----------------------------------------------------------------------
-- Stored procedure setting client class indirect dependency on KNOWN or
-- UNKNOWN built-in classes by checking this flag for the client classes
-- on which it depends.
--
-- Parameters:
-- - client_class_id id of the client class which dependency is set,
-- - dependency_id id of the client class on which the given class depends.
-- -----------------------------------------------------------------------
DELIMITER $$
CREATE PROCEDURE updateDHCPv4ClientClassKnownDependency(IN client_class_id BIGINT UNSIGNED,
                                                        IN dependency_id BIGINT UNSIGNED)
BEGIN
    DECLARE dependency TINYINT;
    -- Check if the dependency class references KNOWN/UNKNOWN.
    SET dependency = (
        SELECT depend_on_known_directly FROM dhcp4_client_class
        WHERE id = dependency_id
    );
    -- If it doesn't, check if the dependency references KNOWN/UNKNOWN
    -- indirectly (via other classes).
    IF dependency = 0 THEN
        SET dependency = (
            SELECT depend_on_known_indirectly FROM dhcp4_client_class_order
            WHERE class_id = dependency_id
        );
    END IF;
    IF dependency <> 0 THEN
        UPDATE dhcp4_client_class_order
            SET depend_on_known_indirectly = 1
        WHERE class_id = client_class_id;
    END IF;
END $$
DELIMITER ;

-- -----------------------------------------------------------------------
-- Trigger setting client class indirect dependency on KNOWN or UNKNOWN
-- built-in classes by checking this flag for the client classes on which
-- it depends.
-- -----------------------------------------------------------------------
DELIMITER $$
CREATE TRIGGER dhcp4_client_class_dependency_AINS AFTER INSERT ON dhcp4_client_class_dependency FOR EACH ROW
BEGIN
    CALL updateDHCPv4ClientClassKnownDependency(NEW.class_id, NEW.dependency_id);
END $$
DELIMITER ;

DROP PROCEDURE IF EXISTS checkDHCPv4ClientClassKnownDependencyChange;

-- -----------------------------------------------------------------------
-- Stored procedure to be executed before committing a transaction
-- updating a DHCPv4 client class. It verifies if the class dependency on
-- KNOWN or UNKNOWN built-in classes has changed as a result of the
-- update. It signals an error if it has changed and there is at least
-- one class depending on this class.
-- -----------------------------------------------------------------------
DELIMITER $$
CREATE PROCEDURE checkDHCPv4ClientClassKnownDependencyChange()
BEGIN
    DECLARE depended TINYINT DEFAULT 0;
    DECLARE depends TINYINT DEFAULT 0;

    -- Session variables are set upon a client class update.
    IF @client_class_id IS NOT NULL THEN
        -- Check if any of the classes depend on this class. If not,
        -- it is ok to change the dependency on KNOWN/UNKNOWN.
        IF EXISTS(
            SELECT 1 FROM dhcp4_client_class_dependency
            WHERE dependency_id = @client_class_id LIMIT 1
        ) THEN
            -- Using the session variables, determine whether the client class
            -- depended on KNOWN/UNKNOWN before the update.
            IF @depend_on_known_directly <> 0 OR @depend_on_known_indirectly <> 0 THEN
                SET depended = 1;
            END IF;
            -- Check if the client class depends on KNOWN/UNKNOWN after the update.
            SET depends = (
                SELECT depend_on_known_directly FROM dhcp4_client_class
                WHERE id = @client_class_id
            );
            -- If it doesn't depend directly, check indirect dependencies.
            IF depends = 0 THEN
                SET depends = (
                    SELECT depend_on_known_indirectly FROM dhcp4_client_class_order
                    WHERE class_id = @client_class_id
                );
            END IF;
            -- The resulting dependency on KNOWN/UNKNOWN must not change.
            IF depended <> depends THEN
                SIGNAL SQLSTATE '45000'
                    SET MESSAGE_TEXT = 'Class dependency on KNOWN/UNKNOWN built-in classes must not change.';
            END IF;
        END IF;
    END IF;
END $$
DELIMITER ;

-- -----------------------------------------------------------------------
-- Create table matching DHCPv4 classes with the servers.
-- -----------------------------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp4_client_class_server (
    class_id bigint unsigned NOT NULL,
    server_id bigint unsigned NOT NULL,
    modification_ts timestamp NULL DEFAULT NULL,
    PRIMARY KEY (class_id,server_id),
    KEY fk_dhcp4_client_class_server_id (server_id),
    CONSTRAINT fk_dhcp4_client_class_class_id FOREIGN KEY (class_id)
        REFERENCES dhcp4_client_class (id)
        ON DELETE CASCADE,
    CONSTRAINT fk_dhcp4_client_class_server_id FOREIGN KEY (server_id)
        REFERENCES dhcp4_server (id)
) ENGINE=InnoDB;

-- -----------------------------------------------------------------------
-- Extend the table holding DHCPv4 option definitions with a nullable
-- column matching option defintions with client classes.
-- -----------------------------------------------------------------------
ALTER TABLE dhcp4_option_def
    ADD COLUMN class_id BIGINT UNSIGNED NULL DEFAULT NULL;

ALTER TABLE dhcp4_option_def
  ADD CONSTRAINT fk_dhcp4_option_def_client_class_id
    FOREIGN KEY (class_id)
    REFERENCES dhcp4_client_class (id)
    ON DELETE CASCADE
    ON UPDATE CASCADE;

-- -----------------------------------------------------------------------
-- Create a table holding the DHCPv6 client classes. Most table
-- columns map directly to respective client class properties in
-- Kea configuration. The depend_on_known_directly column is
-- explicitly set in an insert or update statement to indicate
-- if the client class directly depends on KNOWN or UNKNOWN
-- built-in classes. A caller should determine it by evaluating
-- a test expression before inserting or updating the client
-- class in the database. The nullable follow_class_name column
-- can be used for positioning the inserted or updated client
-- class within the class hierarchy. Set this column value to
-- an existing class name, after which this class should be
-- placed in the class hierarchy. See dhcp6_client_class_order
-- description for the details of how classes are ordered.
-- -----------------------------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp6_client_class (
    id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
    name VARCHAR(128) NOT NULL,
    test TEXT,
    only_if_required TINYINT NOT NULL DEFAULT '0',
    valid_lifetime INT DEFAULT NULL,
    min_valid_lifetime INT DEFAULT NULL,
    max_valid_lifetime INT DEFAULT NULL,
    depend_on_known_directly TINYINT NOT NULL DEFAULT '0',
    follow_class_name VARCHAR(128) DEFAULT NULL,
    modification_ts TIMESTAMP NOT NULL,
    PRIMARY KEY (id),
    UNIQUE KEY id_UNIQUE (id),
    UNIQUE KEY name_UNIQUE (name),
    KEY key_dhcp6_client_class_modification_ts (modification_ts)
) ENGINE=InnoDB;

-- -----------------------------------------------------------------------
-- Create a table for ordering client classes and holding information
-- about indirect dependencies on KNOWN/UKNOWN built-in client classes.
-- Each class in the dhcp6_client_class table has a corresponding row
-- in the dhcp6_client_class_order table. A caller should not modify
-- the contents of this table. Its entries are automatically created
-- upon inserting or updating client classes in the dhcp6_client_classes
-- using triggers. The order_index designates the position of the client
-- class within the class hierarchy. If the follow_class_name value of
-- the dhcp6_client_class table is set to NULL, the client class is
-- appended at the end of the hierarchy. The assigned order_index
-- value for that class is set to a maximum current value + 1.
-- If the follow_client_class specifies a name of an existing class,
-- the generated order_index is set to an id of that class + 1, and
-- the order_index values of the later classes are incremented by 1.
-- The depend_on_known_indirectly column holds a boolean value indicating
-- whether the given class depends on KNOWN/UKNOWN built-in classes
-- via other classes, i.e. it depends on classes that directly or
-- indirectly depend on these built-ins. This value is auto-generated
-- by a trigger on the dhcp6_client_class_dependency table.
-- -----------------------------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp6_client_class_order (
    class_id BIGINT UNSIGNED NOT NULL,
    order_index BIGINT UNSIGNED NOT NULL,
    depend_on_known_indirectly TINYINT NOT NULL DEFAULT '0',
    PRIMARY KEY (class_id),
    KEY key_dhcp6_client_class_order_index (order_index),
    CONSTRAINT fk_dhcp6_client_class_order_class_id FOREIGN KEY (class_id)
        REFERENCES dhcp6_client_class (id) ON DELETE CASCADE
) ENGINE=InnoDB;

DROP TRIGGER IF EXISTS dhcp6_client_class_AINS;
DROP TRIGGER IF EXISTS dhcp6_client_class_AUPD;
DROP TRIGGER IF EXISTS dhcp6_client_class_ADEL;
DROP PROCEDURE IF EXISTS setClientClass6Order;

-- -----------------------------------------------------------------------
-- Stored procedure positioning an inserted or updated client class
-- within the class hierarchy, depending on the value of the
-- follow_class_name parameter.
--
-- Parameters:
-- - id id of the positioned class,
-- - follow_class_name name of the class after which this class should be
--   positioned within the class hierarchy.
-- - old_follow_class_name name of the previous class after which this
--   class was positioned within the class hierarchy.
-- -----------------------------------------------------------------------
DELIMITER $$
CREATE PROCEDURE setClientClass6Order(IN id BIGINT UNSIGNED,
                                      IN follow_class_name VARCHAR(128),
                                      IN old_follow_class_name VARCHAR(128))
proc_label:BEGIN
    -- This variable will be optionally set if the follow_class_name
    -- column value is specified.
    DECLARE follow_class_index BIGINT UNSIGNED;
    DECLARE msg TEXT;

    -- Remember currently used value of depend_on_known_indirectly.
    SET @depend_on_known_indirectly = (
        SELECT depend_on_known_indirectly FROM dhcp6_client_class_order WHERE id = class_id
    );

    -- Bail if the class is updated without re-positioning.
    IF(
        @depend_on_known_indirectly IS NOT NULL AND
        ((follow_class_name IS NULL AND old_follow_class_name IS NULL) OR
         (follow_class_name = old_follow_class_name))
    ) THEN
        -- The depend_on_known_indirectly is set to 0 because this procedure is invoked
        -- whenever the dhcp6_client_class record is updated. Such update may include
        -- test expression changes impacting the dependency on KNOWN/UNKNOWN classes.
        -- This value will be later adjusted when dependencies are inserted.
        UPDATE dhcp6_client_class_order SET depend_on_known_indirectly = 0
            WHERE class_id = id;
        LEAVE proc_label;
    END IF;

    IF follow_class_name IS NOT NULL THEN
        -- Get the position of the class after which the new class should be added.
        SET follow_class_index = (
            SELECT o.order_index FROM dhcp6_client_class AS c
                INNER JOIN dhcp6_client_class_order AS o
                    ON c.id = o.class_id
            WHERE c.name = follow_class_name
        );
        IF follow_class_index IS NULL THEN
            -- The class with a name specified with follow_class_name does
            -- not exist.
            SET msg = CONCAT('Class ', follow_class_name, ' does not exist.');
            SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = msg;
        END IF;
        -- We need to place the new class at the position of follow_class_index + 1.
        -- There may be a class at this position already.
        IF EXISTS(SELECT * FROM dhcp6_client_class_order WHERE order_index = follow_class_index + 1) THEN
            -- There is a class at this position already. Let's move all classes
            -- starting from this position by one to create a spot for the new
            -- class.
            UPDATE dhcp6_client_class_order
                SET order_index = order_index + 1
            WHERE order_index >= follow_class_index + 1
            ORDER BY order_index DESC;
        END IF;
    ELSE
        -- A caller did not specify the follow_class_name value. Let's append the
        -- new class at the end of the hierarchy.
        SET follow_class_index = (SELECT MAX(order_index) FROM dhcp6_client_class_order);
        IF follow_class_index IS NULL THEN
            -- Apparently, there are no classes. Let's start from 0.
            SET follow_class_index = 0;
        END IF;
    END IF;

    -- Check if moving the class doesn't break dependent classes.
    IF EXISTS(
        SELECT 1 FROM dhcp6_client_class_dependency AS d
            INNER JOIN dhcp6_client_class_order AS o
                ON d.class_id = o.class_id
            WHERE d.dependency_id = id AND o.order_index < follow_class_index + 1
        LIMIT 1
    ) THEN
        SET msg = CONCAT('Unable to move class with id ', id, ' because it would break its dependencies');
        SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = msg;
    END IF;

    -- The depend_on_known_indirectly is set to 0 because this procedure is invoked
    -- whenever the dhcp6_client_class record is updated. Such update may include
    -- test expression changes impacting the dependency on KNOWN/UNKNOWN classes.
    -- This value will be later adjusted when dependencies are inserted.
    REPLACE INTO dhcp6_client_class_order(class_id, order_index, depend_on_known_indirectly)
        VALUES (id, follow_class_index + 1, 0);
END $$
DELIMITER ;

-- -----------------------------------------------------------------------
-- Trigger to position an inserted class within the class hierarchy
-- and create audit.
-- -----------------------------------------------------------------------
DELIMITER $$
CREATE TRIGGER dhcp6_client_class_AINS AFTER INSERT ON dhcp6_client_class FOR EACH ROW BEGIN
    CALL setClientClass6Order(NEW.id, NEW.follow_class_name, NULL);
    CALL createAuditEntryDHCP6('dhcp6_client_class', NEW.id, "create");
END $$
DELIMITER ;

-- -----------------------------------------------------------------------
-- Trigger to position an updated class within the class hierarchy,
-- create audit and remember the direct dependency on the
-- KNOWN/UNKNOWN built-in classes before the class update.
-- When updating a client class, it is very important to ensure that
-- its dependency on KNOWN or UNKNOWN built-in client classes is not
-- changed. It is because there may be other classes that depend on
-- these built-ins via this class. Changing the dependency would break
-- the chain of dependencies for other classes. Here, we store the
-- information about the dependency in the session variables. Their
-- values will be compared with the new dependencies after an update.
-- If they change, an error will be signaled.
-- -----------------------------------------------------------------------
DELIMITER $$
CREATE TRIGGER dhcp6_client_class_AUPD AFTER UPDATE ON dhcp6_client_class FOR EACH ROW BEGIN
    SET @depend_on_known_directly = OLD.depend_on_known_directly;
    SET @client_class_id = NEW.id;
    CALL setClientClass6Order(NEW.id, NEW.follow_class_name, OLD.follow_class_name);
    CALL createAuditEntryDHCP6('dhcp6_client_class', NEW.id, "update");
END $$
DELIMITER ;

-- -----------------------------------------------------------------------
-- Trigger to create dhcp6_client_class audit.
-- -----------------------------------------------------------------------
DELIMITER $$
CREATE TRIGGER dhcp6_client_class_ADEL AFTER DELETE ON dhcp6_client_class FOR EACH ROW BEGIN
    CALL createAuditEntryDHCP6('dhcp6_client_class', OLD.id, "delete");
END $$
DELIMITER ;

-- -----------------------------------------------------------------------
-- Create a table associating client classes stored in the
-- dhcp6_client_class table with their dependencies. There is
-- an M:N relationship between these tables. Each class may have
-- many dependencies (created using member operator in test expression),
-- and each class may be a dependency for many other classes. A caller
-- is responsible for inserting dependencies for a class after inserting
-- or updating it in the dhcp6_client_class table. A caller should
-- delete all existing dependencies for an updated client class, evaluate
-- test expression to discover new dependencies (in case test expression
-- has changed), and insert new dependencies to this table.
-- -----------------------------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp6_client_class_dependency (
    class_id BIGINT UNSIGNED NOT NULL,
    dependency_id BIGINT UNSIGNED NOT NULL,
    PRIMARY KEY (class_id,dependency_id),
    KEY dhcp6_client_class_dependency_id_idx (dependency_id),
    CONSTRAINT dhcp6_client_class_class_id FOREIGN KEY (class_id)
        REFERENCES dhcp6_client_class (id) ON DELETE CASCADE,
    CONSTRAINT dhcp6_client_class_dependency_id FOREIGN KEY (dependency_id)
        REFERENCES dhcp6_client_class (id)
) ENGINE=InnoDB;

DROP TRIGGER IF EXISTS dhcp6_client_class_dependency_BINS;
DROP PROCEDURE IF EXISTS checkDHCPv6ClientClassDependency;

-- -----------------------------------------------------------------------
-- Stored procedure verifying if class dependency is met. It includes
-- checking if referenced classes exist, are associated with the same
-- server or all servers, and are defined before the class specified with
-- class_id.
--
-- Parameters:
-- - class_id id client class,
-- - dependency_id id of the dependency.
-- -----------------------------------------------------------------------
DELIMITER $$
CREATE PROCEDURE checkDHCPv6ClientClassDependency(IN class_id BIGINT UNSIGNED,
                                                  IN dependency_id BIGINT UNSIGNED)
BEGIN
    DECLARE class_index BIGINT UNSIGNED;
    DECLARE dependency_index BIGINT UNSIGNED;
    DECLARE err_msg TEXT;

    -- We could check the same with a constraint but later in this
    -- trigger we use this value to verify if the dependencies are
    -- met.
    IF class_id IS NULL THEN
        SIGNAL SQLSTATE '45000'
            SET MESSAGE_TEXT = 'Client class id must not be NULL.';
    END IF;
    IF dependency_id IS NULL THEN
        SIGNAL SQLSTATE '45000'
            SET MESSAGE_TEXT = 'Class dependency id must not be NULL.';
    END IF;
    -- Dependencies on self make no sense.
    IF class_id = dependency_id THEN
        SIGNAL SQLSTATE '45000'
            SET MESSAGE_TEXT = 'Client class must not have dependency on self.';
    END IF;
    -- Check position of our class in the hierarchy.
    SET class_index = (
        SELECT o.order_index FROM dhcp6_client_class AS c
            INNER JOIN dhcp6_client_class_order AS o
                ON c.id = o.class_id
        WHERE c.id = class_id);
    IF class_index IS NULL THEN
        SET err_msg = CONCAT('Client class with id ', class_id, ' does not exist.');
        SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = err_msg;
    END IF;
    -- Check position of the dependency.
    SET dependency_index = (
        SELECT o.order_index FROM dhcp6_client_class AS c
            INNER JOIN dhcp6_client_class_order AS o ON c.id = o.class_id
        WHERE c.id = dependency_id
    );
    IF dependency_index IS NULL THEN
        SET err_msg = CONCAT('Client class with id ', dependency_id, ' does not exist.');
        SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = err_msg;
    END IF;
    -- The dependency must not be later than our class.
    IF dependency_index > class_index THEN
        SET err_msg = CONCAT('Client class with id ', class_id, ' must not depend on class defined later with id ', dependency_id);
        SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = err_msg;
    END IF;

    -- Check if all servers associated with the new class have dependent
    -- classes configured. This catches the cases that class A belongs to
    -- server1 and depends on class B which belongs only to server 2.
    -- It is fine if the class B belongs to all servers in this case.
    -- Make a SELECT on the dhcp6_client_class_server table to gather
    -- all servers to which the class belongs. LEFT JOIN it with the
    -- same table, selecting all records matching the dependency class
    -- and the servers to which the new class belongs. If there are
    -- any NULL records joined it implies that some dependencies are
    -- not met (didn't find a dependency for at least one server).
    IF EXISTS(
        SELECT 1 FROM dhcp6_client_class_server AS t1
            LEFT JOIN dhcp6_client_class_server AS t2
                ON t2.class_id = dependency_id AND (t2.server_id = 1 OR t2.server_id = t1.server_id)
        WHERE t1.class_id = class_id AND t2.server_id IS NULL
        LIMIT 1
    ) THEN
        SET err_msg = CONCAT('Unmet dependencies for client class with id ', class_id);
        SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = err_msg;
    END IF;
END $$
DELIMITER ;

-- -----------------------------------------------------------------------
-- Trigger verifying if class dependency is met. It includes checking
-- if referenced classes exist, are associated with the same server
-- or all servers, and are defined before the class specified with
-- class_id.
-- -----------------------------------------------------------------------
DELIMITER $$
CREATE TRIGGER dhcp6_client_class_check_dependency_BINS BEFORE INSERT ON dhcp6_client_class_dependency FOR EACH ROW
BEGIN
    CALL checkDHCPv6ClientClassDependency(NEW.class_id, NEW.dependency_id);
END $$
DELIMITER ;

DROP TRIGGER IF EXISTS dhcp6_client_class_dependency_AINS;
DROP PROCEDURE IF EXISTS updateDHCPv6ClientClassKnownDependency;

-- -----------------------------------------------------------------------
-- Stored procedure setting client class indirect dependency on KNOWN or
-- UNKNOWN built-in classes by checking this flag for the client classes
-- on which it depends.
--
-- Parameters:
-- - client_class_id id of the client class which dependency is set,
-- - dependency_id id of the client class on which the given class depends.
-- -----------------------------------------------------------------------
DELIMITER $$
CREATE PROCEDURE updateDHCPv6ClientClassKnownDependency(IN client_class_id BIGINT UNSIGNED,
                                                        IN dependency_id BIGINT UNSIGNED)
BEGIN
    DECLARE dependency TINYINT;
    -- Check if the dependency class references KNOWN/UNKNOWN.
    SET dependency = (
        SELECT depend_on_known_directly FROM dhcp6_client_class
        WHERE id = dependency_id
    );
    -- If it doesn't, check if the dependency references KNOWN/UNKNOWN
    -- indirectly (via other classes).
    IF dependency = 0 THEN
        SET dependency = (
            SELECT depend_on_known_indirectly FROM dhcp6_client_class_order
            WHERE class_id = dependency_id
        );
    END IF;
    IF dependency <> 0 THEN
        UPDATE dhcp6_client_class_order
            SET depend_on_known_indirectly = 1
        WHERE class_id = client_class_id;
    END IF;
END $$
DELIMITER ;

-- -----------------------------------------------------------------------
-- Trigger setting client class indirect dependency on KNOWN or UNKNOWN
-- built-in classes by checking this flag for the client classes on which
-- it depends.
-- -----------------------------------------------------------------------
DELIMITER $$
CREATE TRIGGER dhcp6_client_class_dependency_AINS AFTER INSERT ON dhcp6_client_class_dependency FOR EACH ROW
BEGIN
    CALL updateDHCPv6ClientClassKnownDependency(NEW.class_id, NEW.dependency_id);
END $$
DELIMITER ;

DROP PROCEDURE IF EXISTS checkDHCPv6ClientClassKnownDependencyChange;

-- -----------------------------------------------------------------------
-- Stored procedure to be executed before committing a transaction
-- updating a DHCPv6 client class. It verifies if the class dependency on
-- KNOWN or UNKNOWN built-in classes has changed as a result of the
-- update. It signals an error if it has changed and there is at least
-- one class depending on this class.
-- -----------------------------------------------------------------------
DELIMITER $$
CREATE PROCEDURE checkDHCPv6ClientClassKnownDependencyChange()
BEGIN
    DECLARE depended TINYINT DEFAULT 0;
    DECLARE depends TINYINT DEFAULT 0;

    -- Session variables are set upon a client class update.
    IF @client_class_id IS NOT NULL THEN
        -- Check if any of the classes depend on this class. If not,
        -- it is ok to change the dependency on KNOWN/UNKNOWN.
        IF EXISTS(
            SELECT 1 FROM dhcp6_client_class_dependency
            WHERE dependency_id = @client_class_id LIMIT 1
        ) THEN
            -- Using the session variables, determine whether the client class
            -- depended on KNOWN/UNKNOWN before the update.
            IF @depend_on_known_directly <> 0 OR @depend_on_known_indirectly <> 0 THEN
                SET depended = 1;
            END IF;
            -- Check if the client class depends on KNOWN/UNKNOWN after the update.
            SET depends = (
                SELECT depend_on_known_directly FROM dhcp6_client_class
                WHERE id = @client_class_id
            );
            -- If it doesn't depend directly, check indirect dependencies.
            IF depends = 0 THEN
                SET depends = (
                    SELECT depend_on_known_indirectly FROM dhcp6_client_class_order
                    WHERE class_id = @client_class_id
                );
            END IF;
            -- The resulting dependency on KNOWN/UNKNOWN must not change.
            IF depended <> depends THEN
                SIGNAL SQLSTATE '45000'
                    SET MESSAGE_TEXT = 'Class dependency on KNOWN/UNKNOWN built-in classes must not change.';
            END IF;
        END IF;
    END IF;
END $$
DELIMITER ;

-- -----------------------------------------------------------------------
-- Create table matching DHCPv6 classes with the servers.
-- -----------------------------------------------------------------------
CREATE TABLE IF NOT EXISTS dhcp6_client_class_server (
    class_id bigint unsigned NOT NULL,
    server_id bigint unsigned NOT NULL,
    modification_ts timestamp NULL DEFAULT NULL,
    PRIMARY KEY (class_id,server_id),
    KEY fk_dhcp6_client_class_server_id (server_id),
    CONSTRAINT fk_dhcp6_client_class_class_id FOREIGN KEY (class_id)
        REFERENCES dhcp6_client_class (id)
        ON DELETE CASCADE,
    CONSTRAINT fk_dhcp6_client_class_server_id FOREIGN KEY (server_id)
        REFERENCES dhcp6_server (id)
) ENGINE=InnoDB;

-- -----------------------------------------------------------------------
-- Extend the table holding DHCPv6 option definitions with a nullable
-- column matching option defintions with client classes.
-- -----------------------------------------------------------------------
ALTER TABLE dhcp6_option_def
    ADD COLUMN class_id BIGINT UNSIGNED NULL DEFAULT NULL;

ALTER TABLE dhcp6_option_def
  ADD CONSTRAINT fk_dhcp6_option_def_client_class_id
    FOREIGN KEY (class_id)
    REFERENCES dhcp6_client_class (id)
    ON DELETE CASCADE
    ON UPDATE CASCADE;

# Update the schema version number
UPDATE schema_version
    SET version = '10', minor = '0';

# This line concludes the schema upgrade to version 10.

# This line starts the schema upgrade to version 11.

# Reverse index order to improve reclamation query performance
# Add a constraint that any state value added to the lease4 must
# map to a value in the lease_state table.  Note we have to drop
# the foreign keys first, then add them back.
ALTER TABLE lease4 DROP FOREIGN KEY fk_lease4_state;
DROP INDEX lease4_by_state_expire ON lease4;
CREATE INDEX lease4_by_expire_state ON lease4 (expire ASC, state ASC);
ALTER TABLE lease4
    ADD CONSTRAINT fk_lease4_state FOREIGN KEY (state)
    REFERENCES lease_state (state);

ALTER TABLE lease6 DROP FOREIGN KEY fk_lease6_state;
CREATE INDEX lease6_by_expire_state ON lease6 (expire ASC, state ASC);
DROP INDEX lease6_by_state_expire ON lease6;
ALTER TABLE lease6
    ADD CONSTRAINT fk_lease6_state FOREIGN KEY (state)
    REFERENCES lease_state (state);

# Added preferred lifetime columns v6 client classes.
ALTER TABLE dhcp6_client_class
    ADD COLUMN preferred_lifetime INT(10) DEFAULT NULL,
    ADD COLUMN min_preferred_lifetime INT(10) DEFAULT NULL,
    ADD COLUMN max_preferred_lifetime INT(10) DEFAULT NULL;

# Update the schema version number
UPDATE schema_version
    SET version = '11', minor = '0';

# This line concludes the schema upgrade to version 11.

# This line starts the schema upgrade to version 12.

# Ensure that dhcp_client_class is NULL when an option does not
# belong to any client class. Later, we will add foreign keys for
# the dhcp_client_class columns, and it requires that the columns
# are NULL when there are no corresponding client classes.
SET @disable_audit = 1;
UPDATE dhcp4_options SET dhcp_client_class = NULL
    WHERE scope_id <> 2;
UPDATE dhcp6_options SET dhcp_client_class = NULL
    WHERE scope_id <> 2;
SET @disable_audit = 0;

# Add a foreign keys referencing a client classes. If an option is
# associated with a client class, the option will be deleted
# along with the deleted client class.
ALTER TABLE dhcp4_options
    ADD CONSTRAINT fk_dhcp4_options_client_class
        FOREIGN KEY (dhcp_client_class)
    REFERENCES dhcp4_client_class (name)
    ON DELETE CASCADE ON UPDATE CASCADE;

ALTER TABLE dhcp6_options
    ADD CONSTRAINT fk_dhcp6_options_client_class
        FOREIGN KEY (dhcp_client_class)
    REFERENCES dhcp6_client_class (name)
    ON DELETE CASCADE ON UPDATE CASCADE;

# Update the schema version number
UPDATE schema_version
    SET version = '12', minor = '0';

-- This line concludes the schema upgrade to version 12.

-- This line starts the schema upgrade to version 13.

-- Create a function that separates a contiguous hexadecimal string
-- into groups of two hexadecimals separated by colons.
DROP FUNCTION IF EXISTS colonSeparatedHex;
DELIMITER $$
CREATE FUNCTION colonSeparatedHex(hex VARCHAR(64))
RETURNS VARCHAR(64)
DETERMINISTIC
BEGIN
    -- Declarations
    DECLARE i INT;
    DECLARE length INT;
    DECLARE output VARCHAR(64);

    -- Initializations
    SET i = 3;
    SET length = LENGTH(hex);

    -- Add a leading zero if the first octet has a single hexadecimal character.
    IF MOD(length, 2) = 1 THEN
        SET hex = CONCAT('0', hex);
        SET length = length + 1;
    END IF;

    -- Start with the first octet.
    SET output = SUBSTR(hex, 1, 2);

    -- Add one octet at a time and a leading colon with each.
    label: WHILE i < length DO
        SET output = CONCAT(output, ':', SUBSTR(hex, i, 2));
        SET i = i + 2;
    END WHILE label;

    -- Memfile uses lowercase hexadecimals.
    SET output = LOWER(output);

    RETURN output;
END $$
DELIMITER ;

-- Modify the procedure to output a memfile-ready CSV file.
DROP PROCEDURE IF EXISTS lease4DumpData;
DELIMITER $$
CREATE PROCEDURE lease4DumpData()
BEGIN
    SELECT
        INET_NTOA(address),
        IFNULL(colonSeparatedHex(HEX(hwaddr)), ''),
        IFNULL(colonSeparatedHex(HEX(client_id)), ''),
        valid_lifetime,
        UNIX_TIMESTAMP(expire),
        subnet_id,
        fqdn_fwd,
        fqdn_rev,
        REPLACE(hostname, ',', '&#x2c'),
        state,
        REPLACE(IFNULL(user_context, ''), ',', '&#x2c')
    FROM lease4
    ORDER BY address;
END $$
DELIMITER ;

-- hwtype and hwaddr_source need to be last to match memfile format.
DROP PROCEDURE IF EXISTS lease6DumpHeader;
DELIMITER $$
CREATE PROCEDURE lease6DumpHeader()
BEGIN
    SELECT 'address,duid,valid_lifetime,expire,subnet_id,pref_lifetime,lease_type,iaid,prefix_len,fqdn_fwd,fqdn_rev,hostname,hwaddr,state,user_context,hwtype,hwaddr_source';
END  $$
DELIMITER ;

-- Modify the procedure to output a memfile-ready CSV file.
DROP PROCEDURE IF EXISTS lease6DumpData;
DELIMITER $$
CREATE PROCEDURE lease6DumpData()
BEGIN
    SELECT
        address,
        IFNULL(colonSeparatedHex(HEX(duid)), ''),
        valid_lifetime,
        UNIX_TIMESTAMP(expire),
        subnet_id,
        pref_lifetime,
        lease_type,
        iaid,
        prefix_len,
        fqdn_fwd,
        fqdn_rev,
        REPLACE(hostname, ',', '&#x2c'),
        IFNULL(colonSeparatedHex(HEX(hwaddr)), ''),
        state,
        REPLACE(IFNULL(user_context, ''), ',', '&#x2c'),
        hwtype,
        hwaddr_source
    FROM lease6
    ORDER BY address;
END $$
DELIMITER ;

-- Create a procedure that inserts a v4 lease from memfile data.
DELIMITER $$
CREATE PROCEDURE lease4Upload(
    IN address VARCHAR(15),
    IN hwaddr VARCHAR(20),
    IN client_id VARCHAR(128),
    IN valid_lifetime INT UNSIGNED,
    IN expire BIGINT UNSIGNED,
    IN subnet_id INT UNSIGNED,
    IN fqdn_fwd TINYINT,
    IN fqdn_rev TINYINT,
    IN hostname VARCHAR(255),
    IN state INT UNSIGNED,
    IN user_context TEXT
)
BEGIN
    INSERT INTO lease4 (
        address,
        hwaddr,
        client_id,
        valid_lifetime,
        expire,
        subnet_id,
        fqdn_fwd,
        fqdn_rev,
        hostname,
        state,
        user_context
    ) VALUES (
        INET_ATON(address),
        UNHEX(REPLACE(hwaddr, ':', '')),
        UNHEX(REPLACE(client_id, ':', '')),
        valid_lifetime,
        FROM_UNIXTIME(expire),
        subnet_id,
        fqdn_fwd,
        fqdn_rev,
        REPLACE(hostname, '&#x2c', ','),
        state,
        REPLACE(user_context, '&#x2c', ',')
    );
END $$
DELIMITER ;

-- Create a procedure that inserts a v6 lease from memfile data.
DELIMITER $$
CREATE PROCEDURE lease6Upload(
    IN address VARCHAR(39),
    IN duid VARCHAR(128),
    IN valid_lifetime INT UNSIGNED,
    IN expire BIGINT UNSIGNED,
    IN subnet_id INT UNSIGNED,
    IN pref_lifetime INT UNSIGNED,
    IN lease_type TINYINT,
    IN iaid INT UNSIGNED,
    IN prefix_len TINYINT UNSIGNED,
    IN fqdn_fwd TINYINT,
    IN fqdn_rev TINYINT,
    IN hostname VARCHAR(255),
    IN hwaddr VARCHAR(64),
    IN state INT UNSIGNED,
    IN user_context TEXT,
    IN hwtype SMALLINT,
    IN hwaddr_source INT UNSIGNED
)
BEGIN
    INSERT INTO lease6 (
        address,
        duid,
        valid_lifetime,
        expire,
        subnet_id,
        pref_lifetime,
        lease_type,
        iaid,
        prefix_len,
        fqdn_fwd,
        fqdn_rev,
        hostname,
        hwaddr,
        state,
        user_context,
        hwtype,
        hwaddr_source
    ) VALUES (
        address,
        UNHEX(REPLACE(duid, ':', '')),
        valid_lifetime,
        FROM_UNIXTIME(expire),
        subnet_id,
        pref_lifetime,
        lease_type,
        iaid,
        prefix_len,
        fqdn_fwd,
        fqdn_rev,
        REPLACE(hostname, '&#x2c', ','),
        UNHEX(REPLACE(hwaddr, ':', '')),
        state,
        REPLACE(user_context, '&#x2c', ','),
        hwtype,
        hwaddr_source
    );
END $$
DELIMITER ;

-- Update the schema version number.
UPDATE schema_version
    SET version = '13', minor = '0';

-- This line concludes the schema upgrade to version 13.

-- This line starts the schema upgrade to version 14.

-- Modify shared-network-name foreign key constraint on dhcp4_subnet to not perform
-- the update when the network is deleted the cascaded update will not execute
-- dhcp4_subnet update trigger leaving the updated subnets without audit_entries.
ALTER TABLE dhcp4_subnet
    DROP FOREIGN KEY fk_dhcp4_subnet_shared_network;

ALTER TABLE dhcp4_subnet
    ADD CONSTRAINT fk_dhcp4_subnet_shared_network FOREIGN KEY (shared_network_name)
        REFERENCES dhcp4_shared_network (name)
        ON DELETE NO ACTION ON UPDATE NO ACTION;

-- Modify BEFORE delete trigger on dhcp4_shared_network to explicitly
-- update dhcp4_subnets. This ensures there are audit entries for updated
-- subnets.
DROP TRIGGER dhcp4_shared_network_BDEL;

DELIMITER $$
CREATE TRIGGER dhcp4_shared_network_BDEL BEFORE DELETE ON dhcp4_shared_network
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP4('dhcp4_shared_network', OLD.id, "delete");
        -- In MySQL Foreign key constraint triggered updates will not cascade, so we explicitly
        -- update subnets first which should ensure they get audit entries.
        UPDATE dhcp4_subnet SET shared_network_name = NULL WHERE shared_network_name = OLD.name;
        DELETE FROM dhcp4_options WHERE shared_network_name = OLD.name;
    END $$
DELIMITER ;

-- Modify shared-network-name foreign key constraint on dhcp6_subnet to not perform
-- the update when the network is deleted the cascaded update will not execute
-- dhcp6_subnet update trigger leaving the updated subnets without audit_entries.
ALTER TABLE dhcp6_subnet
    DROP FOREIGN KEY fk_dhcp6_subnet_shared_network;

ALTER TABLE dhcp6_subnet
    ADD CONSTRAINT fk_dhcp6_subnet_shared_network FOREIGN KEY (shared_network_name)
        REFERENCES dhcp6_shared_network (name)
        ON DELETE NO ACTION ON UPDATE NO ACTION;

-- Modify BEFORE delete trigger on dhcp6_shared_network to explicitly
-- update dhcp6_subnets. This ensures there are audit entries for updated
-- subnets.
DROP TRIGGER dhcp6_shared_network_BDEL;

DELIMITER $$
CREATE TRIGGER dhcp6_shared_network_BDEL BEFORE DELETE ON dhcp6_shared_network
    FOR EACH ROW
    BEGIN
        CALL createAuditEntryDHCP6('dhcp6_shared_network', OLD.id, "delete");
        -- In MySQL Foreign key constraint triggered updates will not cascade, so we explicitly
        -- update subnets first which should ensure they get audit entries.
        UPDATE dhcp6_subnet SET shared_network_name = NULL WHERE shared_network_name = OLD.name;
        DELETE FROM dhcp6_options WHERE shared_network_name = OLD.name;
    END $$
DELIMITER ;

-- Add user_context column to client class tables.
ALTER TABLE dhcp4_client_class ADD COLUMN user_context LONGTEXT NULL;
ALTER TABLE dhcp6_client_class ADD COLUMN user_context LONGTEXT NULL;

-- Schema changes related to lease limiting start here. --

-- Recreate the triggers that update the leaseX_stat tables as stored procedures. --

DROP PROCEDURE IF EXISTS lease4_AINS_lease4_stat;
DELIMITER $$
CREATE PROCEDURE lease4_AINS_lease4_stat(IN new_state TINYINT,
                                         IN new_subnet_id INT UNSIGNED)
BEGIN
    IF new_state = 0 OR new_state = 1 THEN
        -- Update the state count if it exists.
        UPDATE lease4_stat SET leases = leases + 1
            WHERE subnet_id = new_subnet_id AND state = new_state;

        -- Insert the state count record if it does not exist.
        IF ROW_COUNT() <= 0 THEN
            INSERT INTO lease4_stat VALUES (new_subnet_id, new_state, 1);
        END IF;
    END IF;
END $$
DELIMITER ;

DROP PROCEDURE IF EXISTS lease4_AUPD_lease4_stat;
DELIMITER $$
CREATE PROCEDURE lease4_AUPD_lease4_stat(IN old_state TINYINT,
                                         IN old_subnet_id INT UNSIGNED,
                                         IN new_state TINYINT,
                                         IN new_subnet_id INT UNSIGNED)
BEGIN
    IF old_subnet_id != new_subnet_id OR old_state != new_state THEN
        IF old_state = 0 OR old_state = 1 THEN
            -- Decrement the old state count if record exists.
            UPDATE lease4_stat
                SET leases = IF(leases > 0, leases - 1, 0)
                WHERE subnet_id = old_subnet_id AND state = old_state;
        END IF;

        IF new_state = 0 OR new_state = 1 THEN
            -- Increment the new state count if record exists.
            UPDATE lease4_stat SET leases = leases + 1
                WHERE subnet_id = new_subnet_id AND state = new_state;

            -- Insert new state record if it does not exist.
            IF ROW_COUNT() <= 0 THEN
                INSERT INTO lease4_stat VALUES (new_subnet_id, new_state, 1);
            END IF;
        END IF;
    END IF;
END $$
DELIMITER ;

DROP PROCEDURE IF EXISTS lease4_ADEL_lease4_stat;
DELIMITER $$
CREATE PROCEDURE lease4_ADEL_lease4_stat(IN old_state TINYINT,
                                         IN old_subnet_id INT UNSIGNED)
BEGIN
    IF old_state = 0 OR old_state = 1 THEN
        -- Decrement the state count if record exists.
        UPDATE lease4_stat
            SET leases = IF(leases > 0, leases - 1, 0)
            WHERE subnet_id = old_subnet_id AND old_state = state;
    END IF;
END $$
DELIMITER ;

DROP PROCEDURE IF EXISTS lease6_AINS_lease6_stat;
DELIMITER $$
CREATE PROCEDURE lease6_AINS_lease6_stat(IN new_state TINYINT,
                                         IN new_subnet_id INT UNSIGNED,
                                         IN new_lease_type TINYINT)
BEGIN
    IF new_state = 0 OR new_state = 1 THEN
        -- Update the state count if it exists.
        UPDATE lease6_stat SET leases = leases + 1
            WHERE subnet_id = new_subnet_id AND lease_type = new_lease_type
            AND state = new_state;

        -- Insert the state count record if it does not exist.
        IF ROW_COUNT() <= 0 THEN
            INSERT INTO lease6_stat VALUES (new_subnet_id, new_lease_type, new_state, 1);
        END IF;
    END IF;
END $$
DELIMITER ;

DROP PROCEDURE IF EXISTS lease6_AUPD_lease6_stat;
DELIMITER $$
CREATE PROCEDURE lease6_AUPD_lease6_stat(IN old_state TINYINT,
                                         IN old_subnet_id INT UNSIGNED,
                                         IN old_lease_type TINYINT,
                                         IN new_state TINYINT,
                                         IN new_subnet_id INT UNSIGNED,
                                         IN new_lease_type TINYINT)
BEGIN
    IF old_subnet_id != new_subnet_id OR
       old_lease_type != new_lease_type OR
       old_state != new_state THEN
        IF old_state = 0 OR old_state = 1 THEN
            -- Decrement the old state count if record exists.
            UPDATE lease6_stat
                SET leases = IF(leases > 0, leases - 1, 0)
                WHERE subnet_id = old_subnet_id AND lease_type = old_lease_type
                AND state = old_state;
        END IF;

        IF new_state = 0 OR new_state = 1 THEN
            -- Increment the new state count if record exists
            UPDATE lease6_stat SET leases = leases + 1
                WHERE subnet_id = new_subnet_id AND lease_type = new_lease_type
                AND state = new_state;

            -- Insert new state record if it does not exist
            IF ROW_COUNT() <= 0 THEN
                INSERT INTO lease6_stat
                VALUES (new_subnet_id, new_lease_type, new_state, 1);
            END IF;
        END IF;
    END IF;
END $$
DELIMITER ;

DROP PROCEDURE IF EXISTS lease6_ADEL_lease6_stat;
DELIMITER $$
CREATE PROCEDURE lease6_ADEL_lease6_stat(IN old_state TINYINT,
                                         IN old_subnet_id INT UNSIGNED,
                                         IN old_lease_type TINYINT)
BEGIN
    IF old_state = 0 OR old_state = 1 THEN
        -- Decrement the state count if record exists
        UPDATE lease6_stat
            SET leases = IF(leases > 0, leases - 1, 0)
            WHERE subnet_id = old_subnet_id AND lease_type = old_lease_type
            AND state = old_state;
    END IF;
END $$
DELIMITER ;

-- Create tables that contain the number of active leases. --

DROP TABLE IF EXISTS lease4_stat_by_client_class;
CREATE TABLE lease4_stat_by_client_class (
    client_class VARCHAR(128) NOT NULL PRIMARY KEY,
    leases BIGINT UNSIGNED NOT NULL
) ENGINE = InnoDB;

DROP TABLE IF EXISTS lease6_stat_by_client_class;
CREATE TABLE lease6_stat_by_client_class (
    client_class VARCHAR(128) NOT NULL,
    lease_type TINYINT NOT NULL,
    leases BIGINT UNSIGNED NOT NULL,
    PRIMARY KEY (client_class, lease_type),
    CONSTRAINT fk_lease6_stat_by_client_class_lease_type FOREIGN KEY (lease_type)
        REFERENCES lease6_types (lease_type)
) ENGINE = InnoDB;

-- Create procedures to be called for each row in after-event triggers for
-- INSERT, UPDATE and DELETE on lease tables.

DROP PROCEDURE IF EXISTS lease4_AINS_lease4_stat_by_client_class;
DELIMITER $$
CREATE PROCEDURE lease4_AINS_lease4_stat_by_client_class(IN new_state TINYINT,
                                                         IN new_user_context TEXT)
BEGIN
    -- Declarations
    DECLARE client_classes TEXT;
    DECLARE class VARCHAR(255);
    DECLARE length INT;
    DECLARE i INT;

    -- Ignore ERROR 3141 (22032) at line 1: Invalid JSON text in argument 1 to
    --      function json_extract: "The document is empty." at position 0.
    -- Ignore ERROR 4037 (HY000): Unexpected end of JSON text in argument 1 to function 'json_extract'
    -- These situations are handled with a propagating NULL result from JSON_EXTRACT.
    DECLARE CONTINUE HANDLER FOR 3141 BEGIN END;
    DECLARE CONTINUE HANDLER FOR 4037 BEGIN END;

    -- Only state 0 is needed for lease limiting.
    IF new_state = 0 THEN
        -- Dive into client classes.
        SET client_classes = JSON_EXTRACT(new_user_context, '$."ISC"."client-classes"');
        SET length = JSON_LENGTH(client_classes);

        -- Iterate through all the client classes and increment the lease count for each.
        SET i = 0;
        label: WHILE i < length DO
            SET class = JSON_UNQUOTE(JSON_EXTRACT(client_classes, CONCAT('\$[', i, ']')));

            -- Upsert to increment the lease count.
            UPDATE lease4_stat_by_client_class SET leases = leases + 1
                WHERE client_class = class;
            IF ROW_COUNT() = 0 THEN
                INSERT INTO lease4_stat_by_client_class VALUES (class, 1);
            END IF;

            SET i = i + 1;
        END WHILE label;
    END IF;
END $$
DELIMITER ;

DROP PROCEDURE IF EXISTS lease4_AUPD_lease4_stat_by_client_class;
DELIMITER $$
CREATE PROCEDURE lease4_AUPD_lease4_stat_by_client_class(IN old_state TINYINT,
                                                         IN old_user_context TEXT,
                                                         IN new_state TINYINT,
                                                         IN new_user_context TEXT)
BEGIN
    -- Declarations
    DECLARE old_client_classes TEXT;
    DECLARE new_client_classes TEXT;
    DECLARE class VARCHAR(255);
    DECLARE length INT;
    DECLARE i INT;

    SET old_client_classes = JSON_EXTRACT(old_user_context, '$."ISC"."client-classes"');
    SET new_client_classes = JSON_EXTRACT(new_user_context, '$."ISC"."client-classes"');

    IF old_state != new_state OR old_client_classes != new_client_classes THEN
        -- Check if it's moving away from a counted state.
        IF old_state = 0 THEN
            -- Dive into client classes.
            SET length = JSON_LENGTH(old_client_classes);
            SET i = 0;
            label: WHILE i < length DO
                SET class = JSON_UNQUOTE(JSON_EXTRACT(old_client_classes, CONCAT('\$[', i, ']')));

                -- Decrement the lease count if the record exists.
                UPDATE lease4_stat_by_client_class SET leases = IF(leases > 0, leases - 1, 0)
                    WHERE client_class = class;

                SET i = i + 1;
            END WHILE label;
        END IF;

        -- Check if it's moving into a counted state.
        IF new_state = 0 THEN
            -- Dive into client classes.
            SET length = JSON_LENGTH(new_client_classes);
            SET i = 0;
            label: WHILE i < length DO
                SET class = JSON_UNQUOTE(JSON_EXTRACT(new_client_classes, CONCAT('\$[', i, ']')));

                -- Upsert to increment the lease count.
                UPDATE lease4_stat_by_client_class SET leases = leases + 1
                    WHERE client_class = class;
                IF ROW_COUNT() <= 0 THEN
                    INSERT INTO lease4_stat_by_client_class VALUES (class, 1);
                END IF;

                SET i = i + 1;
            END WHILE label;
        END IF;
    END IF;
END $$
DELIMITER ;

DROP PROCEDURE IF EXISTS lease4_ADEL_lease4_stat_by_client_class;
DELIMITER $$
CREATE PROCEDURE lease4_ADEL_lease4_stat_by_client_class(IN old_state TINYINT,
                                                         IN old_user_context TEXT)
BEGIN
    -- Declarations
    DECLARE client_classes TEXT;
    DECLARE class VARCHAR(255);
    DECLARE length INT;
    DECLARE i INT;

    -- Ignore ERROR 3141 (22032) at line 1: Invalid JSON text in argument 1 to
    --      function json_extract: "The document is empty." at position 0.
    -- Ignore ERROR 4037 (HY000): Unexpected end of JSON text in argument 1 to function 'json_extract'
    -- These situations are handled with a propagating NULL result from JSON_EXTRACT.
    DECLARE CONTINUE HANDLER FOR 3141 BEGIN END;
    DECLARE CONTINUE HANDLER FOR 4037 BEGIN END;

    -- Only state 0 is accounted for in lease limiting.
    IF old_state = 0 THEN
        -- Dive into client classes.
        SET client_classes = JSON_EXTRACT(old_user_context, '$."ISC"."client-classes"');
        SET length = JSON_LENGTH(client_classes);

        SET i = 0;
        label: WHILE i < length DO
            SET class = JSON_UNQUOTE(JSON_EXTRACT(client_classes, CONCAT('\$[', i, ']')));

            -- Decrement the lease count if the record exists.
            UPDATE lease4_stat_by_client_class SET leases = IF(leases > 0, leases - 1, 0)
                WHERE client_class = class;

            SET i = i + 1;
        END WHILE label;
    END IF;
END $$
DELIMITER ;

DROP PROCEDURE IF EXISTS lease6_AINS_lease6_stat_by_client_class;
DELIMITER $$
CREATE PROCEDURE lease6_AINS_lease6_stat_by_client_class(IN new_state TINYINT,
                                                         IN new_user_context TEXT,
                                                         IN new_lease_type TINYINT)
BEGIN
    -- Declarations
    DECLARE client_classes TEXT;
    DECLARE class VARCHAR(255);
    DECLARE length INT;
    DECLARE i INT;

    -- Ignore ERROR 3141 (22032) at line 1: Invalid JSON text in argument 1 to
    --      function json_extract: "The document is empty." at position 0.
    -- Ignore ERROR 4037 (HY000): Unexpected end of JSON text in argument 1 to function 'json_extract'
    -- These situations are handled with a propagating NULL result from JSON_EXTRACT.
    DECLARE CONTINUE HANDLER FOR 3141 BEGIN END;
    DECLARE CONTINUE HANDLER FOR 4037 BEGIN END;

    -- Only state 0 is needed for lease limiting.
    IF new_state = 0 THEN
        -- Dive into client classes.
        SET client_classes = JSON_EXTRACT(new_user_context, '$."ISC"."client-classes"');
        SET length = JSON_LENGTH(client_classes);

        SET i = 0;
        label: WHILE i < length DO
            SET class = JSON_UNQUOTE(JSON_EXTRACT(client_classes, CONCAT('\$[', i, ']')));

            -- Upsert to increment the lease count.
            UPDATE lease6_stat_by_client_class SET leases = leases + 1
                WHERE client_class = class AND lease_type = new_lease_type;
            IF ROW_COUNT() <= 0 THEN
                INSERT INTO lease6_stat_by_client_class VALUES (class, new_lease_type, 1);
            END IF;

            SET i = i + 1;
        END WHILE label;
    END IF;
END $$
DELIMITER ;

DROP PROCEDURE IF EXISTS lease6_AUPD_lease6_stat_by_client_class;
DELIMITER $$
CREATE PROCEDURE lease6_AUPD_lease6_stat_by_client_class(IN old_state TINYINT,
                                                         IN old_user_context TEXT,
                                                         IN old_lease_type TINYINT,
                                                         IN new_state TINYINT,
                                                         IN new_user_context TEXT,
                                                         IN new_lease_type TINYINT)
BEGIN
    -- Declarations
    DECLARE old_client_classes TEXT;
    DECLARE new_client_classes TEXT;
    DECLARE class VARCHAR(255);
    DECLARE length INT;
    DECLARE i INT;

    SET old_client_classes = JSON_EXTRACT(old_user_context, '$."ISC"."client-classes"');
    SET new_client_classes = JSON_EXTRACT(new_user_context, '$."ISC"."client-classes"');

    IF old_state != new_state OR old_client_classes != new_client_classes OR old_lease_type != new_lease_type THEN
        -- Check if it's moving away from a counted state.
        IF old_state = 0 THEN
            -- Dive into client classes.
            SET length = JSON_LENGTH(old_client_classes);
            SET i = 0;
            label: WHILE i < length DO
                SET class = JSON_UNQUOTE(JSON_EXTRACT(old_client_classes, CONCAT('\$[', i, ']')));

                -- Decrement the lease count if the record exists.
                UPDATE lease6_stat_by_client_class SET leases = IF(leases > 0, leases - 1, 0)
                    WHERE client_class = class AND lease_type = old_lease_type;

                SET i = i + 1;
            END WHILE label;
        END IF;

        -- Check if it's moving into a counted state.
        IF new_state = 0 THEN
            -- Dive into client classes.
            SET length = JSON_LENGTH(new_client_classes);
            SET i = 0;
            label: WHILE i < length DO
                SET class = JSON_UNQUOTE(JSON_EXTRACT(new_client_classes, CONCAT('\$[', i, ']')));

                -- Upsert to increment the lease count.
                UPDATE lease6_stat_by_client_class SET leases = leases + 1
                    WHERE client_class = class AND lease_type = new_lease_type;
                IF ROW_COUNT() <= 0 THEN
                    INSERT INTO lease6_stat_by_client_class VALUES (class, new_lease_type, 1);
                END IF;

                SET i = i + 1;
            END WHILE label;
        END IF;
    END IF;
END $$
DELIMITER ;

DROP PROCEDURE IF EXISTS lease6_ADEL_lease6_stat_by_client_class;
DELIMITER $$
CREATE PROCEDURE lease6_ADEL_lease6_stat_by_client_class(IN old_state TINYINT,
                                                         IN old_user_context TEXT,
                                                         IN old_lease_type TINYINT)
BEGIN
    -- Declarations
    DECLARE client_classes TEXT;
    DECLARE class VARCHAR(255);
    DECLARE length INT;
    DECLARE i INT;

    -- Ignore ERROR 3141 (22032) at line 1: Invalid JSON text in argument 1 to
    --      function json_extract: "The document is empty." at position 0.
    -- Ignore ERROR 4037 (HY000): Unexpected end of JSON text in argument 1 to function 'json_extract'
    -- These situations are handled with a propagating NULL result from JSON_EXTRACT.
    DECLARE CONTINUE HANDLER FOR 3141 BEGIN END;
    DECLARE CONTINUE HANDLER FOR 4037 BEGIN END;

    -- Only state 0 is accounted for in lease limiting. But check both states to be consistent with lease6_stat.
    IF old_state = 0 THEN
        -- Dive into client classes.
        SET client_classes = JSON_EXTRACT(old_user_context, '$."ISC"."client-classes"');
        SET length = JSON_LENGTH(client_classes);

        SET i = 0;
        label: WHILE i < length DO
            SET class = JSON_UNQUOTE(JSON_EXTRACT(client_classes, CONCAT('\$[', i, ']')));

            -- Decrement the lease count if the record exists.
            UPDATE lease6_stat_by_client_class SET leases = IF(leases > 0, leases - 1, 0)
                WHERE client_class = class AND lease_type = old_lease_type;

            SET i = i + 1;
        END WHILE label;
    END IF;
END $$
DELIMITER ;

-- Recreate the after-event triggers for INSERT, UPDATE and DELETE on lease tables to call the --
-- stored procedures above in pairs of two: for client classes and for subnets. --

-- Function that establishes whether JSON functions are supported.
-- They should be provided with MySQL>= 5.7, MariaDB >= 10.2.3.
DROP FUNCTION IF EXISTS isJsonSupported;
DELIMITER $$
CREATE FUNCTION isJsonSupported()
RETURNS BOOL
DETERMINISTIC
BEGIN
    DECLARE dummy BOOL;
    DECLARE CONTINUE HANDLER FOR SQLEXCEPTION
        RETURN false;

    SELECT JSON_EXTRACT('{ "foo-bar": 1 }', '$."foo-bar"') INTO dummy;
    RETURN true;
END $$
DELIMITER ;

DROP TRIGGER IF EXISTS stat_lease4_insert;
DROP TRIGGER IF EXISTS lease4_AINS;
DELIMITER $$
CREATE TRIGGER lease4_AINS AFTER INSERT ON lease4 FOR EACH ROW
BEGIN
    CALL lease4_AINS_lease4_stat(NEW.state, NEW.subnet_id);
    IF @json_supported IS NULL THEN
        SELECT isJsonSupported() INTO @json_supported;
    END IF;
    IF @json_supported = 1 THEN
        CALL lease4_AINS_lease4_stat_by_client_class(NEW.state, NEW.user_context);
    END IF;
END $$
DELIMITER ;

DROP TRIGGER IF EXISTS stat_lease4_update;
DROP TRIGGER IF EXISTS lease4_AUPD;
DELIMITER $$
CREATE TRIGGER lease4_AUPD AFTER UPDATE ON lease4 FOR EACH ROW
BEGIN
    CALL lease4_AUPD_lease4_stat(OLD.state, OLD.subnet_id, NEW.state, NEW.subnet_id);
    IF @json_supported IS NULL THEN
        SELECT isJsonSupported() INTO @json_supported;
    END IF;
    IF @json_supported = 1 THEN
        CALL lease4_AUPD_lease4_stat_by_client_class(OLD.state, OLD.user_context, NEW.state, NEW.user_context);
    END IF;
END $$
DELIMITER ;

DROP TRIGGER IF EXISTS stat_lease4_delete;
DROP TRIGGER IF EXISTS lease4_ADEL;
DELIMITER $$
CREATE TRIGGER lease4_ADEL AFTER DELETE ON lease4 FOR EACH ROW
BEGIN
    CALL lease4_ADEL_lease4_stat(OLD.state, OLD.subnet_id);
    IF @json_supported IS NULL THEN
        SELECT isJsonSupported() INTO @json_supported;
    END IF;
    IF @json_supported = 1 THEN
        CALL lease4_ADEL_lease4_stat_by_client_class(OLD.state, OLD.user_context);
    END IF;
END $$
DELIMITER ;

DROP TRIGGER IF EXISTS stat_lease6_insert;
DROP TRIGGER IF EXISTS lease6_AINS;
DELIMITER $$
CREATE TRIGGER lease6_AINS AFTER INSERT ON lease6 FOR EACH ROW
BEGIN
    CALL lease6_AINS_lease6_stat(NEW.state, NEW.subnet_id, NEW.lease_type);
    IF @json_supported IS NULL THEN
        SELECT isJsonSupported() INTO @json_supported;
    END IF;
    IF @json_supported = 1 THEN
        CALL lease6_AINS_lease6_stat_by_client_class(NEW.state, NEW.user_context, NEW.lease_type);
    END IF;
END $$
DELIMITER ;

DROP TRIGGER IF EXISTS stat_lease6_update;
DROP TRIGGER IF EXISTS lease6_AUPD;
DELIMITER $$
CREATE TRIGGER lease6_AUPD AFTER UPDATE ON lease6 FOR EACH ROW
BEGIN
    CALL lease6_AUPD_lease6_stat(OLD.state, OLD.subnet_id, OLD.lease_type, NEW.state, NEW.subnet_id, NEW.lease_type);
    IF @json_supported IS NULL THEN
        SELECT isJsonSupported() INTO @json_supported;
    END IF;
    IF @json_supported = 1 THEN
        CALL lease6_AUPD_lease6_stat_by_client_class(OLD.state, OLD.user_context, OLD.lease_type, NEW.state, NEW.user_context, NEW.lease_type);
    END IF;
END $$
DELIMITER ;

DROP TRIGGER IF EXISTS stat_lease6_delete;
DROP TRIGGER IF EXISTS lease6_ADEL;
DELIMITER $$
CREATE TRIGGER lease6_ADEL AFTER DELETE ON lease6 FOR EACH ROW
BEGIN
    CALL lease6_ADEL_lease6_stat(OLD.state, OLD.subnet_id, OLD.lease_type);
    IF @json_supported IS NULL THEN
        SELECT isJsonSupported() INTO @json_supported;
    END IF;
    IF @json_supported = 1 THEN
        CALL lease6_ADEL_lease6_stat_by_client_class(OLD.state, OLD.user_context, OLD.lease_type);
    END IF;
END $$
DELIMITER ;

-- Create functions that check if the lease limits set in the given user context are exceeded.
-- They return a string describing a limit that is being exceeded, or an empty
-- string if no limits are exceeded. The following format for is assumed for user_context
-- (not all nodes are mandatory and values are given only as examples):
-- { "ISC": { "limits": { "client-classes": [ { "name": "foo", "address-limit": 2, "prefix-limit": 1 } ],
--                        "subnet": { "id": 1, "address-limit": 2, "prefix-limit": 1 } } } }

DROP FUNCTION IF EXISTS checkLease4Limits;
DELIMITER $$
CREATE FUNCTION checkLease4Limits(user_context TEXT)
RETURNS TEXT
READS SQL DATA
BEGIN
    -- Declarations
    DECLARE json_element TEXT;
    DECLARE length INT;
    DECLARE class TEXT;
    DECLARE name VARCHAR(255);
    DECLARE i INT;
    DECLARE lease_limit INT;
    DECLARE lease_count INT;

    -- Dive into client class limits.
    SET json_element = JSON_EXTRACT(user_context, '$."ISC"."limits"."client-classes"');
    SET length = JSON_LENGTH(json_element);

    SET i = 0;
    label: WHILE i < length DO
        -- Get the lease limit for this client class.
        SET class = JSON_EXTRACT(json_element, CONCAT('\$[', i, ']'));
        SET name = JSON_UNQUOTE(JSON_EXTRACT(class, '$.name'));
        SET lease_limit = JSON_EXTRACT(class, '$."address-limit"');

        IF lease_limit IS NOT NULL THEN
            -- Get the lease count for this client class.
            SET lease_count = (SELECT leases FROM lease4_stat_by_client_class WHERE client_class = name);
            IF lease_count IS NULL THEN
                SET lease_count = 0;
            END IF;

            -- Compare. Return immediately if the limit is exceeded.
            IF lease_limit <= lease_count THEN
                RETURN CONCAT('address limit ', lease_limit, ' for client class "', name, '", current lease count ', lease_count);
            END IF;
        END IF;

        SET i = i + 1;
    END WHILE label;

    -- Dive into subnet limits. Reuse i as subnet ID.
    SET json_element = JSON_EXTRACT(user_context, '$.ISC.limits.subnet');
    SET i = JSON_EXTRACT(json_element, '$.id');
    SET lease_limit = JSON_EXTRACT(json_element, '$."address-limit"');

    IF lease_limit IS NOT NULL THEN
        -- Get the lease count for this client class.
        SET lease_count = (SELECT leases FROM lease4_stat WHERE subnet_id = i AND state = 0);
        IF lease_count IS NULL THEN
            SET lease_count = 0;
        END IF;

        -- Compare. Return immediately if the limit is exceeded.
        IF lease_limit <= lease_count THEN
                RETURN CONCAT('address limit ', lease_limit, ' for subnet ID ', i, ', current lease count ', lease_count);
        END IF;
    END IF;

    RETURN '';
END $$
DELIMITER ;

DROP FUNCTION IF EXISTS checkLease6Limits;
DELIMITER $$
CREATE FUNCTION checkLease6Limits(user_context TEXT)
RETURNS TEXT
READS SQL DATA
BEGIN
    -- Declarations
    DECLARE json_element TEXT;
    DECLARE length INT;
    DECLARE class TEXT;
    DECLARE name VARCHAR(255);
    DECLARE i INT;
    DECLARE lease_limit INT;
    DECLARE lease_count INT;

    -- Dive into client class limits.
    SET json_element = JSON_EXTRACT(user_context, '$."ISC"."limits"."client-classes"');
    SET length = JSON_LENGTH(json_element);

    SET i = 0;
    label: WHILE i < length DO
        -- Get the lease limit for this client class.
        SET class = JSON_EXTRACT(json_element, CONCAT('\$[', i, ']'));
        SET name = JSON_UNQUOTE(JSON_EXTRACT(class, '$.name'));

        SET lease_limit = JSON_EXTRACT(class, '$."address-limit"');
        IF lease_limit IS NOT NULL THEN
            -- Get the address count for this client class.
            SET lease_count = (SELECT leases FROM lease6_stat_by_client_class WHERE client_class = name AND lease_type = 0);
            IF lease_count IS NULL THEN
                SET lease_count = 0;
            END IF;

            -- Compare. Return immediately if the limit is exceeded.
            IF lease_limit <= lease_count THEN
                RETURN CONCAT('address limit ', lease_limit, ' for client class "', name, '", current lease count ', lease_count);
            END IF;
        END IF;

        SET lease_limit = JSON_EXTRACT(class, '$."prefix-limit"');
        IF lease_limit IS NOT NULL THEN
            -- Get the prefix count for this client class.
            SET lease_count = (SELECT leases FROM lease6_stat_by_client_class WHERE client_class = name AND lease_type = 2);
            IF lease_count IS NULL THEN
                SET lease_count = 0;
            END IF;

            -- Compare. Return immediately if the limit is exceeded.
            IF lease_limit <= lease_count THEN
                RETURN CONCAT('prefix limit ', lease_limit, ' for client class "', name, '", current lease count ', lease_count);
            END IF;
        END IF;

        SET i = i + 1;
    END WHILE label;

    -- Dive into subnet limits. Reuse i as subnet ID.
    SET json_element = JSON_EXTRACT(user_context, '$.ISC.limits.subnet');
    SET i = JSON_EXTRACT(json_element, '$.id');
    SET lease_limit = JSON_EXTRACT(json_element, '$."address-limit"');
    IF lease_limit IS NOT NULL THEN
        -- Get the lease count for this client class.
        SET lease_count = (SELECT leases FROM lease6_stat WHERE subnet_id = i AND lease_type = 0 AND state = 0);
        IF lease_count IS NULL THEN
            SET lease_count = 0;
        END IF;

        -- Compare. Return immediately if the limit is exceeded.
        IF lease_limit <= lease_count THEN
                RETURN CONCAT('address limit ', lease_limit, ' for subnet ID ', i, ', current lease count ', lease_count);
        END IF;
    END IF;
    SET lease_limit = JSON_EXTRACT(json_element, '$."prefix-limit"');
    IF lease_limit IS NOT NULL THEN
        -- Get the lease count for this client class.
        SET lease_count = (SELECT leases FROM lease6_stat WHERE subnet_id = i AND lease_type = 2 AND state = 0);
        IF lease_count IS NULL THEN
            SET lease_count = 0;
        END IF;

        -- Compare. Return immediately if the limit is exceeded.
        IF lease_limit <= lease_count THEN
            RETURN CONCAT('prefix limit ', lease_limit, ' for subnet ID ', i, ', current lease count ', lease_count);
        END IF;
    END IF;

    RETURN '';
END $$
DELIMITER ;

-- Update the schema version number.
UPDATE schema_version
    SET version = '14', minor = '0';

-- This line concludes the schema upgrade to version 14.

-- This line starts the schema upgrade to version 15.

-- Add cancelled (aka never-send) column to option tables.
ALTER TABLE dhcp4_options
    ADD COLUMN cancelled TINYINT(1) NOT NULL DEFAULT 0;

ALTER TABLE dhcp6_options
    ADD COLUMN cancelled TINYINT(1) NOT NULL DEFAULT 0;

-- Add offer_lifetime column to v4 tables.
ALTER TABLE dhcp4_shared_network
    ADD COLUMN offer_lifetime INT(10) DEFAULT NULL;

ALTER TABLE dhcp4_subnet
    ADD COLUMN offer_lifetime INT(10) DEFAULT NULL;

ALTER TABLE dhcp4_client_class
    ADD COLUMN offer_lifetime INT(10) DEFAULT NULL;

-- Update the schema version number.
UPDATE schema_version
    SET version = '15', minor = '0';

-- This line concludes the schema upgrade to version 15.

-- This line starts the schema upgrade to version 16.

-- Add relay and remote id columns to DHCPv4 leases.
--
-- Note: these columns are only used for indexes, in particular they are
-- not exported by lease4 dump as values are also in the user context
ALTER TABLE lease4
    ADD COLUMN relay_id VARBINARY(128) DEFAULT NULL,
    ADD COLUMN remote_id VARBINARY(128) DEFAULT NULL;

-- Create relay and remote id indexes.
CREATE INDEX lease4_by_relay_id ON lease4 (relay_id);
CREATE INDEX lease4_by_remote_id ON lease4 (remote_id);

-- Update the schema version number.
UPDATE schema_version
    SET version = '16', minor = '0';

-- This line concludes the schema upgrade to version 16.

-- This line starts the schema upgrade to version 17.

-- Add the allocator column to the DHCPv4 tables.
ALTER TABLE dhcp4_subnet ADD COLUMN allocator TEXT NULL;
ALTER TABLE dhcp4_shared_network ADD COLUMN allocator TEXT NULL;

-- Add allocator and pd_allocator to the DHCPv6 subnet tables.
ALTER TABLE dhcp6_subnet ADD COLUMN allocator TEXT NULL;
ALTER TABLE dhcp6_subnet ADD COLUMN pd_allocator TEXT NULL;

-- Add allocator and pd_allocator to the DHCPv6 shared network tables.
ALTER TABLE dhcp6_shared_network ADD COLUMN allocator TEXT NULL;
ALTER TABLE dhcp6_shared_network ADD COLUMN pd_allocator TEXT NULL;

-- Update the schema version number.
UPDATE schema_version
    SET version = '17', minor = '0';

-- This line concludes the schema upgrade to version 17.

-- This line starts the schema upgrade to version 18.

-- Extend lease4 client_id to 255 bytes.
ALTER TABLE lease4
    MODIFY COLUMN client_id VARBINARY(255);

-- Extend hosts dhcp_identifier to 255 bytes.
ALTER TABLE hosts
    MODIFY COLUMN dhcp_identifier VARBINARY(255) NOT NULL;

-- Extend hosts relay_id to 255 bytes.
ALTER TABLE lease4
    MODIFY COLUMN relay_id VARBINARY(255) DEFAULT NULL;

-- Extend hosts remote_id to 255 bytes.
ALTER TABLE lease4
    MODIFY COLUMN remote_id VARBINARY(255) DEFAULT NULL;

-- Extend lease6 duid to 130 bytes.
ALTER TABLE lease6
    MODIFY COLUMN duid VARBINARY(130);

UPDATE lease6 SET duid = UNHEX('000000') WHERE duid = UNHEX('00');

-- Drop and create lease4Upload stored procedure with 255 bytes long client_id.
DROP PROCEDURE IF EXISTS lease4Upload;

-- Create a procedure that inserts a v4 lease from memfile data.
DELIMITER $$
CREATE PROCEDURE lease4Upload(
    IN address VARCHAR(15),
    IN hwaddr VARCHAR(20),
    IN client_id VARCHAR(255),
    IN valid_lifetime INT UNSIGNED,
    IN expire BIGINT UNSIGNED,
    IN subnet_id INT UNSIGNED,
    IN fqdn_fwd TINYINT,
    IN fqdn_rev TINYINT,
    IN hostname VARCHAR(255),
    IN state INT UNSIGNED,
    IN user_context TEXT
)
BEGIN
    INSERT INTO lease4 (
        address,
        hwaddr,
        client_id,
        valid_lifetime,
        expire,
        subnet_id,
        fqdn_fwd,
        fqdn_rev,
        hostname,
        state,
        user_context
    ) VALUES (
        INET_ATON(address),
        UNHEX(REPLACE(hwaddr, ':', '')),
        UNHEX(REPLACE(client_id, ':', '')),
        valid_lifetime,
        FROM_UNIXTIME(expire),
        subnet_id,
        fqdn_fwd,
        fqdn_rev,
        REPLACE(hostname, '&#x2c', ','),
        state,
        REPLACE(user_context, '&#x2c', ',')
    );
END $$
DELIMITER ;

-- Drop and create lease6Upload stored procedure with 130 bytes long duid.
DROP PROCEDURE IF EXISTS lease6Upload;

-- Create a procedure that inserts a v6 lease from memfile data.
DELIMITER $$
CREATE PROCEDURE lease6Upload(
    IN address VARCHAR(39),
    IN duid VARCHAR(130),
    IN valid_lifetime INT UNSIGNED,
    IN expire BIGINT UNSIGNED,
    IN subnet_id INT UNSIGNED,
    IN pref_lifetime INT UNSIGNED,
    IN lease_type TINYINT,
    IN iaid INT UNSIGNED,
    IN prefix_len TINYINT UNSIGNED,
    IN fqdn_fwd TINYINT,
    IN fqdn_rev TINYINT,
    IN hostname VARCHAR(255),
    IN hwaddr VARCHAR(64),
    IN state INT UNSIGNED,
    IN user_context TEXT,
    IN hwtype SMALLINT,
    IN hwaddr_source INT UNSIGNED
)
BEGIN
    INSERT INTO lease6 (
        address,
        duid,
        valid_lifetime,
        expire,
        subnet_id,
        pref_lifetime,
        lease_type,
        iaid,
        prefix_len,
        fqdn_fwd,
        fqdn_rev,
        hostname,
        hwaddr,
        state,
        user_context,
        hwtype,
        hwaddr_source
    ) VALUES (
        address,
        UNHEX(REPLACE(duid, ':', '')),
        valid_lifetime,
        FROM_UNIXTIME(expire),
        subnet_id,
        pref_lifetime,
        lease_type,
        iaid,
        prefix_len,
        fqdn_fwd,
        fqdn_rev,
        REPLACE(hostname, '&#x2c', ','),
        UNHEX(REPLACE(hwaddr, ':', '')),
        state,
        REPLACE(user_context, '&#x2c', ','),
        hwtype,
        hwaddr_source
    );
END $$
DELIMITER ;

-- Update the schema version number.
UPDATE schema_version
    SET version = '18', minor = '0';

-- This line concludes the schema upgrade to version 18.

# Notes:
#
# Indexes
# =======
# It is likely that additional indexes will be needed.  However, the
# increase in lookup performance from these will come at the expense
# of a decrease in performance during insert operations due to the need
# to update the indexes.  For this reason, the need for additional indexes
# will be determined by experiment during performance tests.
#
# The most likely additional indexes will cover the following columns:
#
# hwaddr and client_id
# For lease stability: if a client requests a new lease, try to find an
# existing or recently expired lease for it so that it can keep using the
# same IP address.
#
# Field Sizes
# ===========
# If any of the VARxxx field sizes are altered, the lengths in the MySQL
# backend source file (mysql_lease_mgr.cc) must be correspondingly changed.
#
# Portability
# ===========
# The 'ENGINE = INNODB' on some tables is not portable to another database
# and will need to be removed.
#
# Some columns contain binary data so are stored as VARBINARY instead of
# VARCHAR.  This may be non-portable between databases: in this case, the
# definition should be changed to VARCHAR.