欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页  >  php教程

Prepare statement

程序员文章站 2022-05-20 20:57:09
...
php代码
 query pairs 
 * Expired will be recompile automatically, any update on config should update ctime as well
 *
 * @author Anthony.chen 
 * 2010-2012 reserved
 */
class PSTMT{

	public static $instances = array();

	/**
	 * Loading the prepare statment from DB Connection
	 * The stmts is config linked to DB instance with 'stmts' k=>v array
	 *
	 * @return Boolean
	 */
	public static function prepare($db='default'){
		//Getting statment from config
		$_config = Pexcel::config('database')->$db;
		$_ctime = Arr::get($_config,'ctime',0);
		$_configStmts = Arr::get($_config,'stmts',NULL);
		if($_configStmts != NULL){//There is statments configured
			if(!isset(self::$instances[$db])){
				$_sql = 'select name , EXTRACT(EPOCH FROM prepare_time) as ctime from pg_prepared_statements';
				$_pstmts = DB::query(DB::SELECT,$_sql,true)->execute($db)->as_array();
				if(!$_pstmts){
					self::$instances[$db] = array();
				}else{
					//Log::debug('Before Commpiling,statement Found');
					foreach($_pstmts as $_pstmt){
						self::$instances[$db][$_pstmt->name] = $_pstmt->ctime;
					}
				}
			}
			//Compile the statments
			foreach($_configStmts as $stmtName => $stmtQuery){
				if(isset(self::$instances[$db][$stmtName])){
					if( self::$instances[$db][$stmtName] < $_ctime){
						//Log::debug($stmtName.' Expires');
					}else{
						//Log::debug($stmtName.' Exists');
						continue;
					}
				}
				self::compile($stmtName,$stmtQuery,$db);
			}

		}else{
			throw new Error_Exception('stmts not in config!');
		}
		return True;
	}

	/**
	 * Compile the prepared statment 
	 *
	 * @param String $stmtName, Statement name 
	 * @param String $stmtQuery, Statement query
	 * @param String $db ,Instance name of database
	 *
	 * @return Boolean
	 */
	public static function compile($stmtName, $stmtQuery,$db ='default'){
		if(isset(self::$instances[$db][$stmtName])){ //already Compiled
			//Doing Nothing
			//Log::debug('DEALLOCATE '.$stmtName);
			DB::query(DB::UPDATE,'DEALLOCATE '.$stmtName)->execute($db);
		}
		$_ret = DB::query(DB::SELECT,$stmtQuery,False,NULL,$stmtName)->execute($db)->count();
		//Log::debug(__FUNCTION__.':compiling the pstat:'.$stmtQuery);
		self::$instances[$db][$stmtName] = time();
		return True;
	}

	/**
	 * Execute the prepared statement
	 *
	 * @param String $stmtName, Statement Name
	 * @param Array $params , The parameter to be transfered into query
	 * @param Boolean $as_object, True to fetch result as object
	 * @param String $db, Database Instance name
	 *
	 * @return Array of result set
	 */

	public static function execute($stmtName,$params = array(),$as_object = TRUE,$db = 'default'){
		if(isset(self::$instances[$db][$stmtName])){
			return DB::query(DB::SELECT,NULL,$as_object,$params,$stmtName)->execute($db);
		}else{
			$_config = Pexcel::config('database')->$db;
			$_configStmts = Arr::get($_config,'stmts',NULL);
			//Compile the prepared statment 
			if(isset($_configStmts[$stmtName])){
				self::compile($stmtName,$_configStmts[$stmtName],$db);
			}else{
				return false;
			}
			return DB::query(DB::SELECT,NULL,$as_object,$params,$stmtName)->execute($db);
		}
	}
}
相关标签: Prepare statement