Added SqlGeneratorInterface and implemented it in TableSchema class.

src/Database/Schema/SqlGeneratorInterface.php

@@ -0,0 +1,71 @@
+<?php
+/**
+ * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
+ * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
+ *
+ * Licensed under The MIT License
+ * For full copyright and license information, please see the LICENSE.txt
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright     Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
+ * @link          http://cakephp.org CakePHP(tm) Project
+ * @since         3.5.0
+ * @license       http://www.opensource.org/licenses/mit-license.php MIT License
+ */
+namespace Cake\Database\Schema;
+
+use Cake\Database\Connection;
+
+/**
+ * An interface used by TableSchema objects.
+ */
+interface SqlGeneratorInterface
+{
+
+    /**
+     * Generate the SQL to create the Table.
+     *
+     * Uses the connection to access the schema dialect
+     * to generate platform specific SQL.
+     *
+     * @param \Cake\Database\Connection $connection The connection to generate SQL for.
+     * @return array List of SQL statements to create the table and the
+     *    required indexes.
+     */
+    public function createSql(Connection $connection);
+
+    /**
+     * Generate the SQL to drop a table.
+     *
+     * Uses the connection to access the schema dialect to generate platform
+     * specific SQL.
+     *
+     * @param \Cake\Database\Connection $connection The connection to generate SQL for.
+     * @return array SQL to drop a table.
+     */
+    public function dropSql(Connection $connection);
+
+    /**
+     * Generate the SQL statements to truncate a table
+     *
+     * @param \Cake\Database\Connection $connection The connection to generate SQL for.
+     * @return array SQL to truncate a table.
+     */
+    public function truncateSql(Connection $connection);
+
+    /**
+     * Generate the SQL statements to add the constraints to the table
+     *
+     * @param \Cake\Database\Connection $connection The connection to generate SQL for.
+     * @return array SQL to add the constraints.
+     */
+    public function addConstraintSql(Connection $connection);
+
+    /**
+     * Generate the SQL statements to drop the constraints to the table
+     *
+     * @param \Cake\Database\Connection $connection The connection to generate SQL for.
+     * @return array SQL to drop a table.
+     */
+    public function dropConstraintSql(Connection $connection);
+}

src/Database/Schema/TableSchema.php

@@ -30,7 +30,7 @@ use Cake\Datasource\SchemaInterface;
  * Schema\Collection objects. They can also be converted into SQL using the
  * createSql(), dropSql() and truncateSql() methods.
  */
-class TableSchema implements SchemaInterface
+class TableSchema implements SchemaInterface, SqlGeneratorInterface
 {
 
     /**