protected static function CacheGetKey($iPortalId = null)
    {
        if (is_null($iPortalId)) {
            $portal = self::getPortalDomainService()->getActivePortal();
            if (null !== $portal) {
                $iPortalId = $portal->id;
            }
        }
        $aKey = array('class' => 'TdbShop', 'ident' => 'objectInstance', 'portalid' => $iPortalId);

        return TCacheManager::GetKey($aKey);
    }