<?php /** * @link http://www.yiiframework.com/ * @copyright Copyright (c) 2008 Yii Software LLC * @license http://www.yiiframework.com/license/ */ namespace yii\db; /** * 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, * * ```php * $expression = new Expression('NOW()'); * $now = (new \yii\db\Query)->select($expression)->scalar(); // SELECT NOW(); * echo $now; // prints the current date * ``` * * Expression objects are mainly created for passing raw SQL expressions to methods of * [[Query]], [[ActiveQuery]], and related classes. * * An expression can also be bound with parameters specified via [[params]]. * * @author Qiang Xue <qiang.xue@gmail.com> * @since 2.0 */ class Expression extends \yii\base\Object { /** * @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 = []; /** * Constructor. * @param string $expression the DB expression * @param array $params parameters * @param array $config name-value pairs that will be used to initialize the object properties */ public function __construct($expression, $params = [], $config = []) { $this->expression = $expression; $this->params = $params; parent::__construct($config); } /** * String magic method * @return string the DB expression */ public function __toString() { return $this->expression; } }