protected function checkDriverSupport( $driver ){
		if( !in_array( $driver, $this->drivers ) )
			throw new \RuntimeException( 'PDO driver "'.$driver.'" is not supported' );
		if( !in_array( $driver, \PDO::getAvailableDrivers() ) )
			throw new \RuntimeException( 'PDO driver "'.$driver.'" is not loaded' );
	}