static public function getCTARolesForSiteTarget($nb_site_target)
    {
        $nb_site_target_id = nb_getMixedValue($nb_site_target, NABU_SITE_TARGET_FIELD_ID);
        if (is_numeric($nb_site_target_id)) {
            $retval = CNabuEngine::getEngine()
                    ->getMainDB()
                    ->getQueryAsObjectArray(
                        '\nabu\data\site\CNabuSiteTargetCTARole', null,
                        'select stcr.* '
                        . 'from nb_site_target_cta stc, nb_site_target_cta_role stcr '
                       . 'where stc.nb_site_target_cta_id=stcr.nb_site_target_cta_id '
                         . 'and stc.nb_site_target_id=%target_id$d',
                        array(
                            'target_id' => $nb_site_target_id
                        )
                    )
            ;
        } else {
            $retval = null;
        }

        return $retval;
    }