Starting to implement a TupleComparison expression class, this will be

used for eager loading associations with composite foreignKeys

Cake/Database/Expression/Comparison.php

@@ -1,7 +1,5 @@
 <?php
 /**
- * PHP Version 5.4
- *
  * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
  * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
  *
@@ -58,18 +56,17 @@ class Comparison extends QueryExpression {
  * @return void
  */
 	public function __construct($field, $value, $type, $conjuntion) {
-		$this->_field = $field;
-		$this->_value = $value;
+		$this->field($field);
+		$this->value($value);
 		$this->type($conjuntion);
 
 		if (is_string($type)) {
 			$this->_type = $type;
 		}
+
 		if (is_string($field) && isset($types[$this->_field])) {
 			$this->_type = current($types);
 		}
-
-		$this->_conditions[$field] = $value;
 	}
 
 /**

Cake/Database/Expression/TupleComparison.php

@@ -0,0 +1,59 @@
+<?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         CakePHP(tm) v 3.0.0
+ * @license       MIT License (http://www.opensource.org/licenses/mit-license.php)
+ */
+namespace Cake\Database\Expression;
+
+use Cake\Database\Expression\Compariso;
+use Cake\Database\ValueBinder;
+
+/**
+ *
+ */
+class TupleComparison extends Comparison {
+
+/**
+ * Constructor
+ *
+ * @param string $field the field name to compare to a value
+ * @param mixed $value the value to be used in comparison
+ * @param string $type the type name used to cast the value
+ * @param string $conjunction the operator used for comparing field and value
+ * @return void
+ */
+	public function __construct($field, $value, $type = [], $conjuntion = '=') {
+		parent::__construct($field, $value, $type, $conjuntion);
+		$this->_type = (array)$type;
+	}
+
+/**
+ * Convert the expression into a SQL fragment.
+ *
+ * @param Cake\Database\ValueBinder $generator Placeholder generator object
+ * @return string
+ */
+	public function sql(ValueBinder $generator) {
+		$template = '(%s) %s (%s)';
+		$values = [];
+		foreach ($this->getValue() as $i => $value) {
+			$values[] = $this->_bindValue(
+				$generator,
+				$value,
+				isset($this->_type[$i]) ? $this->_type[$i] : null
+			);
+		}
+		$field = implode(', ', (array)$this->getField());
+		return sprintf($template, $field, $this->_conjunction, implode(', ', $values));
+	}
+
+}

Test/TestCase/Database/Expression/IdentifierExpressionTest.php

@@ -1,6 +1,5 @@
 <?php
 /**
- * PHP Version 5.4
  *
  * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
  * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)

Test/TestCase/Database/Expression/TupleComparisonTest.php

@@ -0,0 +1,42 @@
+<?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         CakePHP(tm) v 3.0.0
+ * @license       MIT License (http://www.opensource.org/licenses/mit-license.php)
+ */
+namespace Cake\Test\TestCase\Database\Expression;
+
+use Cake\Database\Expression\TupleComparison;
+use Cake\Database\ValueBinder;
+use Cake\TestSuite\TestCase;
+
+/**
+ * Tests TupleComparison class
+ *
+ **/
+class TupleComparisonTest extends TestCase {
+
+/**
+ * Tests generating a function with no arguments
+ *
+ * @return void
+ */
+	public function testsSimpleTuple() {
+		$f = new TupleComparison(['field1', 'field2'], [1, 2], ['integer', 'integer'], '=');
+		$binder = new ValueBinder;
+		$this->assertEquals('(field1, field2) = (:c0, :c1)', $f->sql($binder));
+		$this->assertSame(1, $binder->bindings()[':c0']['value']);
+		$this->assertSame(2, $binder->bindings()[':c1']['value']);
+		$this->assertSame('integer', $binder->bindings()[':c0']['type']);
+		$this->assertSame('integer', $binder->bindings()[':c1']['type']);
+	}
+
+}