Question

使用CSqlDataProvider时，是否可以从sql server查询缓存数据。如果是这样，任何人都可以提供一些关于它的文档的链接。或者，如果您亲自完成，请指导。

我做了一次搜索，却一无所获:(

Answer 1

There is实现此功能的一些示例

<?php
class CachedSqlDataProvider extends CDataProvider
{
        public $queryCache;
        public $queryCacheLife;

        /**
         * @var CDbConnection the database connection to be used in the queries.
         * Defaults to null, meaning using Yii::app()->db.
         */

        public $db;
        /**
         * @var string the SQL statement to be used for fetching data rows.
         */
        public $sql;
        /**
         * @var array parameters (name=>value) to be bound to the SQL statement.
         */
        public $params=array();
        /**
         * @var string the name of key field. Defaults to 'id'.
         */
        public $keyField='id';

        /**
         * Constructor.
         * @param string $sql the SQL statement to be used for fetching data rows.
         * @param array $config configuration (name=>value) to be applied as the initial property values of this class.
         */
        public function __construct($sql,$config=array())
        {
                $this->sql=$sql;
                foreach($config as $key=>$value)
                        $this->$key=$value;
        }

        /**
         * Fetches the data from the persistent data storage.
         * @return array list of data items
         */
        protected function fetchData()
        {
                $sql=$this->sql;
                $db=$this->db===null ? Yii::app()->db : $this->db;
                $db->active=true;

                if(($sort=$this->getSort())!==false)
                {
                        $order=$sort->getOrderBy();
                        if(!empty($order))
                        {
                                if(preg_match('/\s+order\s+by\s+[\w\s,]+$/i',$sql))
                                        $sql.=', '.$order;
                                else
                                        $sql.=' ORDER BY '.$order;
                        }
                }

                if(($pagination=$this->getPagination())!==false)
                {
                        $pagination->setItemCount($this->getTotalItemCount());
                        $limit=$pagination->getLimit();
                        $offset=$pagination->getOffset();
                        $sql=$db->getCommandBuilder()->applyLimit($sql,$limit,$offset);
                }

                if( $this->queryCache == true && $this->queryCacheLife > 0 )
                        $command=$db->cache( $this->queryCacheLife )->createCommand($sql);
                else
                        $command=$db->createCommand($sql);

                foreach($this->params as $name=>$value)
                        $command->bindValue($name,$value);

                return $command->queryAll();
        }

        /**
         * Fetches the data item keys from the persistent data storage.
         * @return array list of data item keys.
         */
        protected function fetchKeys()
        {
                $keys=array();
                foreach($this->getData() as $i=>$data)
                        $keys[$i]=$data[$this->keyField];
                return $keys;
        }

        /**
         * Calculates the total number of data items.
         * This method is invoked when {@link getTotalItemCount()} is invoked
         * and {@link totalItemCount} is not set previously.
         * The default implementation simply returns 0.
         * You may override this method to return accurate total number of data items.
         * @return integer the total number of data items.
         */
        protected function calculateTotalItemCount()
        {
                return 0;
        }
}
?>

Yii-使用CSqlDataprovider进行缓存

1 个答案: