public function addChildComponentRow($type, $childComponentRow = null)
    {
        $r = $this->createChildRow('ChildComponents');
        $r->component = $type;
        $r->nr = $this->getMaxChildComponentNr($type)+1;
        $r->saved = 0;
        $r->save();

        if ($childComponentRow) {
            $childComponentRow->component_id = $this->component_id.'-'.substr($type, 0, 1).$r->nr;
        }
        return $r;
    }