DbDependency.php 2.02 KB
Newer Older
Qiang Xue committed
1 2 3
<?php
/**
 * @link http://www.yiiframework.com/
Qiang Xue committed
4
 * @copyright Copyright (c) 2008 Yii Software LLC
Qiang Xue committed
5 6 7
 * @license http://www.yiiframework.com/license/
 */

Qiang Xue committed
8 9
namespace yii\caching;

Qiang Xue committed
10
use Yii;
11
use yii\base\InvalidConfigException;
Qiang Xue committed
12
use yii\db\Connection;
Qiang Xue committed
13

Qiang Xue committed
14
/**
Qiang Xue committed
15
 * DbDependency represents a dependency based on the query result of a SQL statement.
Qiang Xue committed
16
 *
Qiang Xue committed
17
 * If the query result changes, the dependency is considered as changed.
Qiang Xue committed
18
 * The query is specified via the [[sql]] property.
Qiang Xue committed
19 20
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
Qiang Xue committed
21
 * @since 2.0
Qiang Xue committed
22
 */
Qiang Xue committed
23
class DbDependency extends Dependency
Qiang Xue committed
24 25
{
	/**
26
	 * @var string the application component ID of the DB connection.
Qiang Xue committed
27
	 */
28
	public $db = 'db';
Qiang Xue committed
29
	/**
Qiang Xue committed
30
	 * @var string the SQL query whose result is used to determine if the dependency has been changed.
31
	 * Only the first row of the query result will be used.
Qiang Xue committed
32
	 */
Qiang Xue committed
33
	public $sql;
Qiang Xue committed
34
	/**
resurtm committed
35
	 * @var array the parameters (name => value) to be bound to the SQL statement specified by [[sql]].
Qiang Xue committed
36
	 */
37
	public $params = [];
Qiang Xue committed
38 39 40 41

	/**
	 * Generates the data needed to determine if dependency has been changed.
	 * This method returns the value of the global state.
42
	 * @param Cache $cache the cache component that is currently evaluating this dependency
Qiang Xue committed
43
	 * @return mixed the data needed to determine if dependency has been changed.
44
	 * @throws InvalidConfigException if [[db]] is not a valid application component ID
Qiang Xue committed
45
	 */
46
	protected function generateDependencyData($cache)
Qiang Xue committed
47
	{
48 49 50 51
		$db = Yii::$app->getComponent($this->db);
		if (!$db instanceof Connection) {
			throw new InvalidConfigException("DbDependency::db must be the application component ID of a DB connection.");
		}
52 53 54
		if ($this->sql === null) {
			throw new InvalidConfigException("DbDependency::sql must be set.");
		}
55

56
		if ($db->enableQueryCache) {
Qiang Xue committed
57
			// temporarily disable and re-enable query caching
58
			$db->enableQueryCache = false;
59
			$result = $db->createCommand($this->sql, $this->params)->queryOne();
60
			$db->enableQueryCache = true;
Qiang Xue committed
61
		} else {
62
			$result = $db->createCommand($this->sql, $this->params)->queryOne();
Qiang Xue committed
63
		}
Qiang Xue committed
64
		return $result;
Qiang Xue committed
65 66
	}
}