fix: add missing abstract methods

Author: kenjis

system/Database/BaseConnection.php

@@ -1481,6 +1481,13 @@ public function disableForeignKeyChecks()
         return $this->query($sql);
     }
 
+    /**
+     * Returns platform-specific SQL to disable foreign key checks.
+     *
+     * @return string
+     */
+    abstract protected function _disableForeignKeyChecks();
+
     /**
      * Enables foreign key checks temporarily.
      */
@@ -1491,6 +1498,13 @@ public function enableForeignKeyChecks()
         return $this->query($sql);
     }
 
+    /**
+     * Returns platform-specific SQL to enable foreign key checks.
+     *
+     * @return string
+     */
+    abstract protected function _enableForeignKeyChecks();
+
     /**
      * Allows the engine to be set into a mode where queries are not
      * actually executed, but they are still generated, timed, etc.

system/Test/Mock/MockConnection.php

@@ -230,4 +230,14 @@ protected function _transRollback(): bool
     {
         return true;
     }
+
+    protected function _disableForeignKeyChecks()
+    {
+        return '';
+    }
+
+    protected function _enableForeignKeyChecks()
+    {
+        return '';
+    }
 }