Expression.php 1.47 KB
Newer Older
w  
Qiang Xue committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
<?php
/**
 * Expression class file.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.yiiframework.com/
 * @copyright Copyright &copy; 2008-2012 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace yii\db\dao;

/**
 * Expression represents a DB expression that does not need escaping or quoting.
 * When an Expression object is embedded within a SQL statement or fragment,
 * it will be replaced with the [[expression]] property value without any
 * DB escaping or quoting. For example,
 *
 * ~~~
 * $expression = new Expression('NOW()');
 * $sql = 'SELECT ' . $expression;  // SELECT NOW()
 * ~~~
 *
 * An expression can also be bound with parameters specified via [[params]].
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @since 2.0
 */
Qiang Xue committed
29
class Expression extends \yii\base\Object
w  
Qiang Xue committed
30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61
{
	/**
	 * @var string the DB expression
	 */
	public $expression;
	/**
	 * @var array list of parameters that should be bound for this expression.
	 * The keys are placeholders appearing in [[expression]] and the values
	 * are the corresponding parameter values.
	 */
	public $params = array();

	/**
	 * Constructor.
	 * @param string $expression the DB expression
	 * @param array $params parameters
	 */
	public function __construct($expression, $params = array())
	{
		$this->expression = $expression;
		$this->params = $params;
	}

	/**
	 * String magic method
	 * @return string the DB expression
	 */
	public function __toString()
	{
		return $this->expression;
	}
}