Yii2 Bootstrap 3
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<?php
/**
* @link http://www.yiiframework.com/
* @copyright Copyright (c) 2008 Yii Software LLC
* @license http://www.yiiframework.com/license/
*/
namespace yii\caching;
use Yii;
use yii\base\InvalidConfigException;
use yii\db\Connection;
/**
* DbDependency represents a dependency based on the query result of a SQL statement.
*
* If the query result changes, the dependency is considered as changed.
* The query is specified via the [[sql]] property.
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @since 2.0
*/
class DbDependency extends Dependency
{
/**
* @var string the application component ID of the DB connection.
*/
public $db = 'db';
/**
* @var string the SQL query whose result is used to determine if the dependency has been changed.
* Only the first row of the query result will be used.
*/
public $sql;
/**
* @var array the parameters (name => value) to be bound to the SQL statement specified by [[sql]].
*/
public $params;
/**
* Constructor.
* @param string $sql the SQL query whose result is used to determine if the dependency has been changed.
* @param array $params the parameters (name => value) to be bound to the SQL statement specified by [[sql]].
* @param array $config name-value pairs that will be used to initialize the object properties
*/
public function __construct($sql, $params = array(), $config = array())
{
$this->sql = $sql;
$this->params = $params;
parent::__construct($config);
}
/**
* Generates the data needed to determine if dependency has been changed.
* This method returns the value of the global state.
* @param Cache $cache the cache component that is currently evaluating this dependency
* @return mixed the data needed to determine if dependency has been changed.
* @throws InvalidConfigException if [[db]] is not a valid application component ID
*/
protected function generateDependencyData($cache)
{
$db = Yii::$app->getComponent($this->db);
if (!$db instanceof Connection) {
throw new InvalidConfigException("DbDependency::db must be the application component ID of a DB connection.");
}
if ($db->enableQueryCache) {
// temporarily disable and re-enable query caching
$db->enableQueryCache = false;
$result = $db->createCommand($this->sql, $this->params)->queryOne();
$db->enableQueryCache = true;
} else {
$result = $db->createCommand($this->sql, $this->params)->queryOne();
}
return $result;
}
}