LMongo\Query\Builder::renameField PHP 메소드

    public function renameField($old, $new = null)
    {
        if (is_array($old)) {
            $update = array('$rename' => $old);
        } else {
            $update = array('$rename' => array($old => $new));
        }
        return $this->performUpdate($update);
    }