public function addCat()
    {
        $config = \OxidEsales\Eshop\Core\Registry::getConfig();
        $categoriesToAdd = $this->_getActionIds('oxcategories.oxid');
        $oxId = \OxidEsales\Eshop\Core\Registry::getConfig()->getRequestParameter('synchoxid');
        $shopId = $config->getShopId();
        $objectToCategoryView = $this->_getViewName('oxobject2category');

        // adding
        if (\OxidEsales\Eshop\Core\Registry::getConfig()->getRequestParameter('all')) {
            $categoriesTable = $this->_getViewName('oxcategories');
            $categoriesToAdd = $this->_getAll($this->_addFilter("select $categoriesTable.oxid " . $this->_getQuery()));
        }

        if (isset($categoriesToAdd) && is_array($categoriesToAdd)) {
            // We force reading from master to prevent issues with slow replications or open transactions (see ESDEV-3804 and ESDEV-3822).
            $database = \OxidEsales\Eshop\Core\DatabaseProvider::getMaster();

            $objectToCategory = oxNew(\OxidEsales\Eshop\Application\Model\Object2Category::class);

            foreach ($categoriesToAdd as $sAdd) {
                // check, if it's already in, then don't add it again
                $sSelect = "select 1 from " . $objectToCategoryView . " as oxobject2category where oxobject2category.oxcatnid= "
                           . $database->quote($sAdd) . " and oxobject2category.oxobjectid = " . $database->quote($oxId) . " ";
                if ($database->getOne($sSelect)) {
                    continue;
                }

                $objectToCategory->setId(md5($oxId . $sAdd . $shopId));
                $objectToCategory->oxobject2category__oxobjectid = new \OxidEsales\Eshop\Core\Field($oxId);
                $objectToCategory->oxobject2category__oxcatnid = new \OxidEsales\Eshop\Core\Field($sAdd);
                $objectToCategory->oxobject2category__oxtime = new \OxidEsales\Eshop\Core\Field(time());

                $objectToCategory->save();
            }

            $this->_updateOxTime($oxId);

            $this->resetArtSeoUrl($oxId);
            $this->resetContentCache();
            $this->onCategoriesAdd($categoriesToAdd);
        }
    }