reverts new interface

src/Database/Expression/IdentifierExpression.php

@@ -14,13 +14,13 @@
  */
 namespace Cake\Database\Expression;
 
-use Cake\Database\IdentifierInterface;
+use Cake\Database\ExpressionInterface;
 use Cake\Database\ValueBinder;
 
 /**
  * Represents a single identifier name in the database
  */
-class IdentifierExpression implements IdentifierInterface
+class IdentifierExpression implements ExpressionInterface
 {
 
     /**

src/Database/IdentifierInterface.php

@@ -1,36 +0,0 @@
-<?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         3.4.1
- * @license       http://www.opensource.org/licenses/mit-license.php MIT License
- */
-namespace Cake\Database;
-
-/**
- * Represents a single identifier name in the database
- */
-interface IdentifierInterface extends ExpressionInterface
-{
-    /**
-     * Returns the identifier this expression represents
-     *
-     * @return string
-     */
-    public function getIdentifier();
-
-    /**
-     * Sets the identifier this expression represents
-     *
-     * @param string $identifier The identifier
-     * @return void
-     */
-    public function setIdentifier($identifier);
-}

src/Database/Query.php

@@ -1476,7 +1476,7 @@ class Query implements ExpressionInterface, IteratorAggregate
      * ```
      *
      * @param string $identifier The identifier for an expression
-     * @return \Cake\Database\IdentifierInterface
+     * @return \Cake\Database\ExpressionInterface
      */
     public function identifier($identifier)
     {