Nette\Database\Table\GroupedSelection::getRefTable PHP Method

    protected function getRefTable(&$refPath)
    {
        $refObj = $this->refTable;
        $refPath = $this->name . '.';
        while ($refObj instanceof self) {
            $refPath .= $refObj->name . '.';
            $refObj = $refObj->refTable;
        }
        return $refObj;
    }