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70 lines
2.2 KiB
PHP
70 lines
2.2 KiB
PHP
<?php
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/**
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* @link http://www.yiiframework.com/
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* @copyright Copyright (c) 2008 Yii Software LLC
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* @license http://www.yiiframework.com/license/
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*/
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namespace yii\caching;
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use Yii;
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use yii\base\InvalidConfigException;
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use yii\db\Connection;
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use yii\di\Instance;
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/**
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* DbDependency represents a dependency based on the query result of a SQL statement.
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*
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* If the query result changes, the dependency is considered as changed.
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* The query is specified via the [[sql]] property.
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*
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* For more details and usage information on Cache, see the [guide article on caching](guide:caching-overview).
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*
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* @author Qiang Xue <qiang.xue@gmail.com>
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* @since 2.0
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*/
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class DbDependency extends Dependency
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{
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/**
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* @var string the application component ID of the DB connection.
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*/
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public $db = 'db';
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/**
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* @var string the SQL query whose result is used to determine if the dependency has been changed.
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* Only the first row of the query result will be used.
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*/
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public $sql;
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/**
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* @var array the parameters (name => value) to be bound to the SQL statement specified by [[sql]].
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*/
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public $params = [];
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/**
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* Generates the data needed to determine if dependency has been changed.
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* This method returns the value of the global state.
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* @param CacheInterface $cache the cache component that is currently evaluating this dependency
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* @return mixed the data needed to determine if dependency has been changed.
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* @throws InvalidConfigException if [[db]] is not a valid application component ID
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*/
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protected function generateDependencyData($cache)
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{
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/* @var $db Connection */
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$db = Instance::ensure($this->db, Connection::className());
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if ($this->sql === null) {
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throw new InvalidConfigException('DbDependency::sql must be set.');
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}
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if ($db->enableQueryCache) {
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// temporarily disable and re-enable query caching
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$db->enableQueryCache = false;
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$result = $db->createCommand($this->sql, $this->params)->queryOne();
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$db->enableQueryCache = true;
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} else {
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$result = $db->createCommand($this->sql, $this->params)->queryOne();
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}
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return $result;
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}
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}
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