PDO singleton model

 "SET NAMES ".DB_CHARSET); if(!self::$PDOInstance) { try { self::$PDOInstance = new PDO($dsn, DB_USER, DB_PASSWD, $driver_options); self::$PDOInstance->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); } catch (PDOException $e) { die($e->getMessage()); } } return self::$PDOInstance; } } //使用 $pdo = new IPDO(); ?>