public static function GetInstance($DB_TYPE = DB_TYPE, $DB_HOST = DB_HOST, $DB_NAME = DB_NAME, $DB_USER = DB_USER, $DB_PASS = DB_PASSWORD) { if (!isset(self::$instance)) { self::$instance = new self($DB_TYPE, $DB_HOST, $DB_NAME, $DB_USER, $DB_PASS); } return self::$instance; }