[#2299] Create subnet audit entry when network is deleted

    Update subnets in shared-network BDEL trigger rather than
    relying on foreign key update action

new files:
    src/share/database/scripts/mysql/upgrade_013_to_014.sh.in
    src/share/database/scripts/pgsql/upgrade_011_to_012.sh.in

configure.ac
    added:
    src/share/database/scripts/mysql/upgrade_013_to_014.sh
    src/share/database/scripts/pgsql/upgrade_011_to_012.sh

src/bin/admin/tests/mysql_tests.sh.in
    added 13 to 14 checks
src/bin/admin/tests/pgsql_tests.sh.in
    added 11 to 12 checks

src/hooks/dhcp/mysql_cb/tests/mysql_cb_dhcp4_unittest.cc
src/hooks/dhcp/mysql_cb/tests/mysql_cb_dhcp6_unittest.cc
    enabled disabled tests

src/lib/dhcpsrv/testutils/generic_cb_dhcp4_unittest.cc
    GenericConfigBackendDHCPv4Test::getAllSharedNetworks4Test()
    - updated expected audit entry order

src/lib/dhcpsrv/testutils/generic_cb_dhcp6_unittest.cc
    GenericConfigBackendDHCPv6Test::getAllSharedNetworks6Test()
    - updated expected audit entry order

src/lib/mysql/mysql_constants.h
    Updated schema version to 14

src/lib/pgsql/pgsql_connection.h
    Updated schema version to 12

src/share/database/scripts/mysql/.gitignore
src/share/database/scripts/mysql/Makefile.am
    added upgrade_013_to_014.sh

src/share/database/scripts/mysql/dhcpdb_create.mysql
    subnet rows are now updated directly in shared-network
    BEFORE delete triggers (v4 and v6)

src/share/database/scripts/pgsql/Makefile.am
    added upgrade_011_to_012.sh

src/share/database/scripts/pgsql/dhcpdb_create.pgsql
    subnet rows are now updated directly in shared-network
    BEFORE delete triggers (v4 and v6)

17 files changed, 416 insertions, 21 deletions

diff --git a/configure.ac b/configure.ac
index 7d79c7524b..01c648683e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1631,6 +1631,8 @@ AC_CONFIG_FILES([src/share/database/scripts/mysql/upgrade_011_to_012.sh],
                 [chmod +x src/share/database/scripts/mysql/upgrade_011_to_012.sh])
 AC_CONFIG_FILES([src/share/database/scripts/mysql/upgrade_012_to_013.sh],
                 [chmod +x src/share/database/scripts/mysql/upgrade_012_to_013.sh])
+AC_CONFIG_FILES([src/share/database/scripts/mysql/upgrade_013_to_014.sh],
+                [chmod +x src/share/database/scripts/mysql/upgrade_013_to_014.sh])
 AC_CONFIG_FILES([src/share/database/scripts/mysql/wipe_data.sh],
                 [chmod +x src/share/database/scripts/mysql/wipe_data.sh])
 AC_CONFIG_FILES([src/share/database/scripts/pgsql/Makefile])
@@ -1666,6 +1668,8 @@ AC_CONFIG_FILES([src/share/database/scripts/pgsql/upgrade_009_to_010.sh],
                 [chmod +x src/share/database/scripts/pgsql/upgrade_009_to_010.sh])
 AC_CONFIG_FILES([src/share/database/scripts/pgsql/upgrade_010_to_011.sh],
                 [chmod +x src/share/database/scripts/pgsql/upgrade_010_to_011.sh])
+AC_CONFIG_FILES([src/share/database/scripts/pgsql/upgrade_011_to_012.sh],
+                [chmod +x src/share/database/scripts/pgsql/upgrade_011_to_012.sh])
 AC_CONFIG_FILES([src/share/database/scripts/pgsql/wipe_data.sh],
                 [chmod +x src/share/database/scripts/pgsql/wipe_data.sh])
 AC_CONFIG_FILES([src/share/yang/Makefile])
diff --git a/src/bin/admin/tests/mysql_tests.sh.in b/src/bin/admin/tests/mysql_tests.sh.in
index 2402bce5eb..65e955c805 100644
--- a/src/bin/admin/tests/mysql_tests.sh.in
+++ b/src/bin/admin/tests/mysql_tests.sh.in
@@ -375,6 +375,26 @@ mysql_upgrade_12_to_13_test() {
     assert_str_eq '' "${OUTPUT}"
 }
 
+mysql_upgrade_13_to_14_test() {
+   # Check function source code
+    run_command \
+         mysql_execute "select action_statement from information_schema.TRIGGERS where trigger_schema = '${db_name}' and trigger_name = 'dhcp4_shared_network_BDEL'";
+
+    assert_eq 0 "${EXIT_CODE}" "function func_dhcp4_shared_network_BDEL() broken or missing. (expected status code %d, returned %d)"
+
+    count=$(echo "${OUTPUT}" | grep -Eci 'UPDATE dhcp4_subnet SET shared_network_name = NULL') || true
+    assert_eq 1 "${count}" "function func_dhcp4_shared_network_BDEL() is missing changed line. (expected count %d, returned %d)"
+
+   # Check function source code
+    run_command \
+         mysql_execute "select action_statement from information_schema.TRIGGERS where trigger_schema = '${db_name}' and trigger_name = 'dhcp6_shared_network_BDEL'";
+
+    assert_eq 0 "${EXIT_CODE}" "function func_dhcp6_shared_network_BDEL() broken or missing. (expected status code %d, returned %d)"
+
+    count=$(echo "${OUTPUT}" | grep -Eci 'UPDATE dhcp6_subnet SET shared_network_name = NULL') || true
+    assert_eq 1 "${count}" "function func_dhcp6_shared_network_BDEL() is missing changed line. (expected count %d, returned %d)"
+}
+
 mysql_upgrade_test() {
 
     test_start "mysql.upgrade"
@@ -389,14 +409,14 @@ mysql_upgrade_test() {
     version=$("${kea_admin}" db-version mysql -u "${db_user}" -p "${db_password}" -n "${db_name}" -d "${db_scripts_dir}")
     assert_str_eq "1.0" "${version}" "Expected kea-admin to return %s, returned value was %s"
 
-    # Ok, we have a 1.0 database. Let's upgrade it to 13.0.
+    # Ok, we have a 1.0 database. Let's upgrade it to 14.0.
     run_command \
         "${kea_admin}" db-upgrade mysql -u "${db_user}" -p "${db_password}" -n "${db_name}" -d "${db_scripts_dir}"
     assert_eq 0 "${EXIT_CODE}" "kea-admin db-upgrade mysql failed, expected %d, returned non-zero status code %d\n"
 
-    # Verify upgraded schema reports version 13.0.
+    # Verify upgraded schema reports version 14.0.
     version=$("${kea_admin}" db-version mysql -u "${db_user}" -p "${db_password}" -n "${db_name}" -d "${db_scripts_dir}")
-    assert_str_eq "13.0" "${version}" "Expected kea-admin to return %s, returned value was %s"
+    assert_str_eq "14.0" "${version}" "Expected kea-admin to return %s, returned value was %s"
 
     # Let's check that the new tables are indeed there.
 
@@ -1020,6 +1040,9 @@ SET @disable_audit = 0;"
     # Check upgrade from 12.0 to 13.0.
     mysql_upgrade_12_to_13_test
 
+    # Check upgrade from 13.0 to 14.0.
+    mysql_upgrade_13_to_14_test
+
     # Let's wipe the whole database
     mysql_wipe
 
diff --git a/src/bin/admin/tests/pgsql_tests.sh.in b/src/bin/admin/tests/pgsql_tests.sh.in
index 25268bb1ff..40baa83ef8 100644
--- a/src/bin/admin/tests/pgsql_tests.sh.in
+++ b/src/bin/admin/tests/pgsql_tests.sh.in
@@ -143,7 +143,7 @@ pgsql_db_version_test() {
     run_command \
         "${kea_admin}" db-version pgsql -u "${db_user}" -p "${db_password}" -n "${db_name}"
     version="${OUTPUT}"
-    assert_str_eq "11.0" "${version}" "Expected kea-admin to return %s, returned value was %s"
+    assert_str_eq "12.0" "${version}" "Expected kea-admin to return %s, returned value was %s"
 
     # Let's wipe the whole database
     pgsql_wipe
@@ -460,6 +460,28 @@ pgsql_upgrade_10_0_to_11_0() {
     assert_eq 1 "${count}" "function createOptionAuditDHCP6() is missing changed line. (expected count %d, returned %d)"
 }
 
+pgsql_upgrade_11_0_to_12_0() {
+    run_command \
+        pgsql_execute "$session_sql"
+
+    # Check function source code
+    run_command \
+         pgsql_execute "select proname,prosrc from pg_proc where proname='func_dhcp4_shared_network_bdel'"
+
+    assert_eq 0 "${EXIT_CODE}" "function func_dhcp4_shared_network_BDEL() broken or missing. (expected status code %d, returned %d)"
+
+    count=$(echo "${OUTPUT}" | grep -Eci 'UPDATE dhcp4_subnet SET shared_network_name = NULL') || true
+    assert_eq 1 "${count}" "function func_dhcp4_shared_network_BDEL() is missing changed line. (expected count %d, returned %d)"
+
+    # Check function source code
+    run_command \
+         pgsql_execute "select proname,prosrc from pg_proc where proname='func_dhcp6_shared_network_bdel'"
+
+    assert_eq 0 "${EXIT_CODE}" "function func_dhcp6_shared_network_BDEL() broken or missing. (expected status code %d, returned %d)"
+
+    count=$(echo "${OUTPUT}" | grep -Eci 'UPDATE dhcp6_subnet SET shared_network_name = NULL') || true
+    assert_eq 1 "${count}" "function func_dhcp6_shared_network_BDEL() is missing changed line. (expected count %d, returned %d)"
+}
 
 pgsql_upgrade_test() {
     test_start "pgsql.upgrade-test"
@@ -476,9 +498,9 @@ pgsql_upgrade_test() {
         "${kea_admin}" db-upgrade pgsql -u "${db_user}" -p "${db_password}" -n "${db_name}" -d "${db_scripts_dir}"
     assert_eq 0 "${EXIT_CODE}" "db-upgrade failed, expected exit code: %d, actual: %d"
 
-    # Verify upgraded schema reports version 11.0.
+    # Verify upgraded schema reports version 12.0.
     version=$("${kea_admin}" db-version pgsql -u "${db_user}" -p "${db_password}" -n "${db_name}" -d "${db_scripts_dir}")
-    assert_str_eq "11.0" "${version}" 'Expected kea-admin to return %s, returned value was %s'
+    assert_str_eq "12.0" "${version}" 'Expected kea-admin to return %s, returned value was %s'
 
     # Check 1.0 to 2.0 upgrade
     pgsql_upgrade_1_0_to_2_0
@@ -507,6 +529,9 @@ pgsql_upgrade_test() {
     # Check 10.0 to 11.0 upgrade
     pgsql_upgrade_10_0_to_11_0
 
+    # Check 11.0 to 12.0 upgrade
+    pgsql_upgrade_11_0_to_12_0
+
     # Let's wipe the whole database
     pgsql_wipe
 
diff --git a/src/hooks/dhcp/mysql_cb/tests/mysql_cb_dhcp4_unittest.cc b/src/hooks/dhcp/mysql_cb/tests/mysql_cb_dhcp4_unittest.cc
index af7093c06e..63d1f10599 100644
--- a/src/hooks/dhcp/mysql_cb/tests/mysql_cb_dhcp4_unittest.cc
+++ b/src/hooks/dhcp/mysql_cb/tests/mysql_cb_dhcp4_unittest.cc
@@ -267,8 +267,7 @@ TEST_F(MySqlConfigBackendDHCPv4Test, deleteSharedNetworkSubnets4Test) {
     deleteSharedNetworkSubnets4Test();
 }
 
-/// @todo This test is disabled pending resolution of #2299.
-TEST_F(MySqlConfigBackendDHCPv4Test, DISABLED_getAllSharedNetworks4Test) {
+TEST_F(MySqlConfigBackendDHCPv4Test, getAllSharedNetworks4Test) {
     getAllSharedNetworks4Test();
 }
 
diff --git a/src/hooks/dhcp/mysql_cb/tests/mysql_cb_dhcp6_unittest.cc b/src/hooks/dhcp/mysql_cb/tests/mysql_cb_dhcp6_unittest.cc
index cc05ed25c0..73d889194c 100644
--- a/src/hooks/dhcp/mysql_cb/tests/mysql_cb_dhcp6_unittest.cc
+++ b/src/hooks/dhcp/mysql_cb/tests/mysql_cb_dhcp6_unittest.cc
@@ -267,8 +267,7 @@ TEST_F(MySqlConfigBackendDHCPv6Test, deleteSharedNetworkSubnets6Test) {
     deleteSharedNetworkSubnets6Test();
 }
 
-/// @todo This test is disabled pending resolution of #2299.
-TEST_F(MySqlConfigBackendDHCPv6Test, DISABLED_getAllSharedNetworks6Test) {
+TEST_F(MySqlConfigBackendDHCPv6Test, getAllSharedNetworks6Test) {
     getAllSharedNetworks6Test();
 }
 
diff --git a/src/lib/dhcpsrv/testutils/generic_cb_dhcp4_unittest.cc b/src/lib/dhcpsrv/testutils/generic_cb_dhcp4_unittest.cc
index 5ab0265656..587a06bd84 100644
--- a/src/lib/dhcpsrv/testutils/generic_cb_dhcp4_unittest.cc
+++ b/src/lib/dhcpsrv/testutils/generic_cb_dhcp4_unittest.cc
@@ -2364,16 +2364,16 @@ GenericConfigBackendDHCPv4Test::getAllSharedNetworks4Test() {
                 AuditEntry::ModificationType::DELETE, "deleted all shared networks"
             },
             {
-                "dhcp4_shared_network",
-                AuditEntry::ModificationType::DELETE, "deleted all shared networks"
-            },
-            {
                 "dhcp4_subnet",
                 AuditEntry::ModificationType::UPDATE, "deleted all shared networks"
             },
             {
                 "dhcp4_subnet",
                 AuditEntry::ModificationType::UPDATE, "deleted all shared networks"
+            },
+            {
+                "dhcp4_shared_network",
+                AuditEntry::ModificationType::DELETE, "deleted all shared networks"
             }
         });
 
diff --git a/src/lib/dhcpsrv/testutils/generic_cb_dhcp6_unittest.cc b/src/lib/dhcpsrv/testutils/generic_cb_dhcp6_unittest.cc
index e2c782938f..eae2097d70 100644
--- a/src/lib/dhcpsrv/testutils/generic_cb_dhcp6_unittest.cc
+++ b/src/lib/dhcpsrv/testutils/generic_cb_dhcp6_unittest.cc
@@ -2391,16 +2391,16 @@ GenericConfigBackendDHCPv6Test::getAllSharedNetworks6Test() {
                 AuditEntry::ModificationType::DELETE, "deleted all shared networks"
             },
             {
-                "dhcp6_shared_network",
-                AuditEntry::ModificationType::DELETE, "deleted all shared networks"
-            },
-            {
                 "dhcp6_subnet",
                 AuditEntry::ModificationType::UPDATE, "deleted all shared networks"
             },
             {
                 "dhcp6_subnet",
                 AuditEntry::ModificationType::UPDATE, "deleted all shared networks"
+            },
+            {
+                "dhcp6_shared_network",
+                AuditEntry::ModificationType::DELETE, "deleted all shared networks"
             }
         });
 
diff --git a/src/lib/mysql/mysql_constants.h b/src/lib/mysql/mysql_constants.h
index f556d061a9..f7f38b9e94 100644
--- a/src/lib/mysql/mysql_constants.h
+++ b/src/lib/mysql/mysql_constants.h
@@ -52,7 +52,7 @@ const int MLM_MYSQL_FETCH_FAILURE = 0;
 
 /// @name Current database schema version values.
 //@{
-const uint32_t MYSQL_SCHEMA_VERSION_MAJOR = 13;
+const uint32_t MYSQL_SCHEMA_VERSION_MAJOR = 14;
 const uint32_t MYSQL_SCHEMA_VERSION_MINOR = 0;
 
 //@}
diff --git a/src/lib/pgsql/pgsql_connection.h b/src/lib/pgsql/pgsql_connection.h
index f0b63e97d3..edd1d8b54d 100644
--- a/src/lib/pgsql/pgsql_connection.h
+++ b/src/lib/pgsql/pgsql_connection.h
@@ -17,8 +17,8 @@
 namespace isc {
 namespace db {
 
-/// @brief Define PostgreSQL backend version: 11.0
-const uint32_t PGSQL_SCHEMA_VERSION_MAJOR = 11;
+/// @brief Define PostgreSQL backend version: 12.0
+const uint32_t PGSQL_SCHEMA_VERSION_MAJOR = 12;
 const uint32_t PGSQL_SCHEMA_VERSION_MINOR = 0;
 
 // Maximum number of parameters that can be used a statement
diff --git a/src/share/database/scripts/mysql/.gitignore b/src/share/database/scripts/mysql/.gitignore
index 8603a6e342..511aa89d33 100644
--- a/src/share/database/scripts/mysql/.gitignore
+++ b/src/share/database/scripts/mysql/.gitignore
@@ -21,4 +21,5 @@
 /upgrade_010_to_011.sh
 /upgrade_011_to_012.sh
 /upgrade_012_to_013.sh
+/upgrade_013_to_014.sh
 /wipe_data.sh
diff --git a/src/share/database/scripts/mysql/Makefile.am b/src/share/database/scripts/mysql/Makefile.am
index 14af57feae..29ba228faf 100644
--- a/src/share/database/scripts/mysql/Makefile.am
+++ b/src/share/database/scripts/mysql/Makefile.am
@@ -32,6 +32,7 @@ mysql_SCRIPTS += upgrade_009.6_to_010.0.sh
 mysql_SCRIPTS += upgrade_010_to_011.sh
 mysql_SCRIPTS += upgrade_011_to_012.sh
 mysql_SCRIPTS += upgrade_012_to_013.sh
+mysql_SCRIPTS += upgrade_013_to_014.sh
 mysql_SCRIPTS += wipe_data.sh
 
 DISTCLEANFILES = ${mysql_SCRIPTS}
diff --git a/src/share/database/scripts/mysql/dhcpdb_create.mysql b/src/share/database/scripts/mysql/dhcpdb_create.mysql
index c63c6b438c..f8038f9b2d 100644
--- a/src/share/database/scripts/mysql/dhcpdb_create.mysql
+++ b/src/share/database/scripts/mysql/dhcpdb_create.mysql
@@ -4286,6 +4286,70 @@ UPDATE schema_version
 
 -- This line concludes database upgrade to version 13.
 
+-- Modify shared-network-name foreign key contraint 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 contraint 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 ;
+
+-- Update the schema version number.
+UPDATE schema_version
+    SET version = '14', minor = '0';
+
+
+
+-- This line concludes database upgrade to version 14.
+
 # Notes:
 #
 # Indexes
diff --git a/src/share/database/scripts/mysql/upgrade_013_to_014.sh.in b/src/share/database/scripts/mysql/upgrade_013_to_014.sh.in
new file mode 100644
index 0000000000..924b1bc566
--- /dev/null
+++ b/src/share/database/scripts/mysql/upgrade_013_to_014.sh.in
@@ -0,0 +1,116 @@
+#!/bin/sh
+
+# Copyright (C) 2022 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/.
+
+# shellcheck disable=SC1091
+# SC1091: Not following: ... was not specified as input (see shellcheck -x).
+
+# Exit with error if commands exit with non-zero and if undefined variables are
+# used.
+set -eu
+
+# shellcheck disable=SC2034
+# SC2034: ... appears unused. Verify use (or export if used externally).
+prefix="@prefix@"
+
+# Include utilities. Use installed version if available and
+# use build version if it isn't.
+if [ -e @datarootdir@/@PACKAGE_NAME@/scripts/admin-utils.sh ]; then
+    . "@datarootdir@/@PACKAGE_NAME@/scripts/admin-utils.sh"
+else
+    . "@abs_top_builddir@/src/bin/admin/admin-utils.sh"
+fi
+
+# Check version.
+version=$(mysql_version "${@}")
+if test "${version}" != "13.0"; then
+    printf 'This script upgrades 13.0 to 14.0. '
+    printf 'Reported version is %s. Skipping upgrade.\n' "${version}"
+    exit 0
+fi
+
+# Get the schema name from database argument. We need this to
+# query information_schema for the right database.
+for arg in "${@}"
+do
+    if ! printf '%s' "${arg}" | grep -Eq '^\-\-'
+    then
+        schema="$arg"
+        break
+    fi
+done
+
+# Make sure we have the schema.
+if [ -z "$schema" ]
+then
+    printf "Could not find database schema name in cmd line args: %s\n" "${*}"
+    exit 255
+fi
+
+mysql "$@" <<EOF
+-- Modify shared-network-name foreign key contraint 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 contraint 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 dhcp4_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 ;
+
+-- Update the schema version number.
+UPDATE schema_version
+    SET version = '14', minor = '0';
+
+-- This line concludes database upgrade to version 14.
+EOF
diff --git a/src/share/database/scripts/pgsql/.gitignore b/src/share/database/scripts/pgsql/.gitignore
index 24ebb76b8d..d2e50568ca 100644
--- a/src/share/database/scripts/pgsql/.gitignore
+++ b/src/share/database/scripts/pgsql/.gitignore
@@ -14,4 +14,5 @@
 /upgrade_008_to_009.sh
 /upgrade_009_to_010.sh
 /upgrade_010_to_011.sh
+/upgrade_011_to_012.sh
 /wipe_data.sh
diff --git a/src/share/database/scripts/pgsql/Makefile.am b/src/share/database/scripts/pgsql/Makefile.am
index 1205cd446d..e0b8ea565e 100644
--- a/src/share/database/scripts/pgsql/Makefile.am
+++ b/src/share/database/scripts/pgsql/Makefile.am
@@ -25,6 +25,7 @@ pgsql_SCRIPTS += upgrade_007_to_008.sh
 pgsql_SCRIPTS += upgrade_008_to_009.sh
 pgsql_SCRIPTS += upgrade_009_to_010.sh
 pgsql_SCRIPTS += upgrade_010_to_011.sh
+pgsql_SCRIPTS += upgrade_011_to_012.sh
 pgsql_SCRIPTS += wipe_data.sh
 
 DISTCLEANFILES = ${pgsql_SCRIPTS}
diff --git a/src/share/database/scripts/pgsql/dhcpdb_create.pgsql b/src/share/database/scripts/pgsql/dhcpdb_create.pgsql
index 7ab2c6bcbc..2daba58b38 100644
--- a/src/share/database/scripts/pgsql/dhcpdb_create.pgsql
+++ b/src/share/database/scripts/pgsql/dhcpdb_create.pgsql
@@ -4913,6 +4913,66 @@ END;$$;
 UPDATE schema_version
     SET version = '11', minor = '0';
 
+-- Schema 11.0 specification ends here.
+
+-- This starts schema update to 12.0.
+
+-- Modify shared-network-name foreign key contraint 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 CONSTRAINT fk_dhcp4_subnet_shared_network,
+    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 function on dhcp4_shared_network to explicitly
+-- update dhcp4_subnets. This ensures there are audit entries for updated
+-- subnets.
+-- Trigger function for dhcp4_shared_network_BDEL called BEFORE DELETE on dhcp4_shared_network
+CREATE OR REPLACE FUNCTION func_dhcp4_shared_network_BDEL() RETURNS TRIGGER AS $dhcp4_shared_network_BDEL$
+BEGIN
+    PERFORM createAuditEntryDHCP4('dhcp4_shared_network', OLD.id, 'delete');
+    -- Explicitly update subnets now rather than via foreign key constraint, this ensures the
+    -- audit entries for subnets will preceded that of the shared-network, keeping the order
+    -- of the entries the same as they are for MySQL.
+    UPDATE dhcp4_subnet SET shared_network_name = NULL  WHERE shared_network_name = OLD.name;
+    DELETE FROM dhcp4_options WHERE shared_network_name = OLD.name;
+    RETURN OLD;
+END;
+$dhcp4_shared_network_BDEL$
+LANGUAGE plpgsql;
+
+-- Modify shared-network-name foreign key contraint 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 CONSTRAINT fk_dhcp6_subnet_shared_network,
+    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 function on dhcp6_shared_network to explicitly
+-- update dhcp6_subnets. This ensures there are audit entries for updated
+-- subnets.
+-- Trigger function for dhcp6_shared_network_BDEL called BEFORE DELETE on dhcp6_shared_network
+CREATE OR REPLACE FUNCTION func_dhcp6_shared_network_BDEL() RETURNS TRIGGER AS $dhcp6_shared_network_BDEL$
+BEGIN
+    PERFORM createAuditEntryDHCP6('dhcp6_shared_network', OLD.id, 'delete');
+    -- Explicitly update subnets now rather than via foreign key constraint, this ensures the
+    -- audit entries for subnets will preceded that of the shared-network, keeping the order
+    -- of the entries the same as they are for MySQL.
+    UPDATE dhcp6_subnet SET shared_network_name = NULL  WHERE shared_network_name = OLD.name;
+    DELETE FROM dhcp6_options WHERE shared_network_name = OLD.name;
+    RETURN OLD;
+END;
+$dhcp6_shared_network_BDEL$
+LANGUAGE plpgsql;
+
+-- Update the schema version number.
+UPDATE schema_version
+    SET version = '12', minor = '0';
+
 -- Commit the script transaction.
 COMMIT;
 
diff --git a/src/share/database/scripts/pgsql/upgrade_011_to_012.sh.in b/src/share/database/scripts/pgsql/upgrade_011_to_012.sh.in
new file mode 100644
index 0000000000..64583e9386
--- /dev/null
+++ b/src/share/database/scripts/pgsql/upgrade_011_to_012.sh.in
@@ -0,0 +1,101 @@
+#!/bin/sh
+
+# Copyright (C) 2022 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/.
+
+# shellcheck disable=SC1091
+# SC1091: Not following: ... was not specified as input (see shellcheck -x).
+
+# Exit with error if commands exit with non-zero and if undefined variables are
+# used.
+set -eu
+
+# shellcheck disable=SC2034
+# SC2034: ... appears unused. Verify use (or export if used externally).
+prefix="@prefix@"
+
+# Include utilities. Use installed version if available and
+# use build version if it isn't.
+if [ -e @datarootdir@/@PACKAGE_NAME@/scripts/admin-utils.sh ]; then
+    . "@datarootdir@/@PACKAGE_NAME@/scripts/admin-utils.sh"
+else
+    . "@abs_top_builddir@/src/bin/admin/admin-utils.sh"
+fi
+
+VERSION=$(pgsql_version "$@")
+
+if [ "$VERSION" != "11.0" ]; then
+    printf 'This script upgrades 11.0 to 12.0. '
+    printf 'Reported version is %s. Skipping upgrade.\n' "${VERSION}"
+    exit 0
+fi
+
+psql "$@" >/dev/null <<EOF
+START TRANSACTION;
+
+-- This starts schema update to 12.0.
+
+-- Modify shared-network-name foreign key contraint 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 CONSTRAINT fk_dhcp4_subnet_shared_network,
+    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 function on dhcp4_shared_network to explicitly
+-- update dhcp4_subnets. This ensures there are audit entries for updated
+-- subnets.
+-- Trigger function for dhcp4_shared_network_BDEL called BEFORE DELETE on dhcp4_shared_network
+CREATE OR REPLACE FUNCTION func_dhcp4_shared_network_BDEL() RETURNS TRIGGER AS \$dhcp4_shared_network_BDEL\$
+BEGIN
+    PERFORM createAuditEntryDHCP4('dhcp4_shared_network', OLD.id, 'delete');
+    -- Explicitly update subnets now rather than via foreign key constraint, this ensures the
+    -- audit entries for subnets will preceded that of the shared-network, keeping the order
+    -- of the entries the same as they are for MySQL.
+    UPDATE dhcp4_subnet SET shared_network_name = NULL  WHERE shared_network_name = OLD.name;
+    DELETE FROM dhcp4_options WHERE shared_network_name = OLD.name;
+    RETURN OLD;
+END;
+\$dhcp4_shared_network_BDEL\$
+LANGUAGE plpgsql;
+
+-- Modify shared-network-name foreign key contraint 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 CONSTRAINT fk_dhcp6_subnet_shared_network,
+    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 function on dhcp6_shared_network to explicitly
+-- update dhcp6_subnets. This ensures there are audit entries for updated
+-- subnets.
+-- Trigger function for dhcp6_shared_network_BDEL called BEFORE DELETE on dhcp6_shared_network
+CREATE OR REPLACE FUNCTION func_dhcp6_shared_network_BDEL() RETURNS TRIGGER AS \$dhcp6_shared_network_BDEL\$
+BEGIN
+    PERFORM createAuditEntryDHCP6('dhcp6_shared_network', OLD.id, 'delete');
+    -- Explicitly update subnets now rather than via foreign key constraint, this ensures the
+    -- audit entries for subnets will preceded that of the shared-network, keeping the order
+    -- of the entries the same as they are for MySQL.
+    UPDATE dhcp6_subnet SET shared_network_name = NULL  WHERE shared_network_name = OLD.name;
+    DELETE FROM dhcp6_options WHERE shared_network_name = OLD.name;
+    RETURN OLD;
+END;
+\$dhcp6_shared_network_BDEL\$
+LANGUAGE plpgsql;
+
+-- Update the schema version number.
+UPDATE schema_version
+    SET version = '12', minor = '0';
+
+-- Commit the script transaction.
+COMMIT;
+
+EOF
+