php - symfony2 query builder with multiple databases (doctrine) -

i want join abteilung table in database other access data.

here right database abteilung:

$manager = $this->getdoctrine()->getmanager('olddb')->getrepository('chrisolduserbundle:bpdepartment'); 

and old query want change:

$result = $this->getdoctrine()->getrepository('kfzbuchungbundle:rent')                 ->createquerybuilder('r')                 ->addselect('abteilung')                 ->addselect('auto')                 ->join('r.auto','auto')                 ->join('r.abteilung','abteilung')                 ->where('r.mietestart >= :date_from')                 ->andwhere('r.mieteende <= :date_to')                 ->setparameter('date_from', $date_from)                 ->setparameter('date_to', $date_to)                 ->orderby('r.mietestart', 'asc')                 ->distinct()                 ->getquery()->getarrayresult(); 

i tried with:

$rsm = new resultsetmapping();             $rsm->addentityresult('chris\kfzbuchungbundle\entity\rent', 'bp');             $rsm->addentityresult('chris\bundle\olduserbundle\entity\bpdepartment', 'bp_dpt');             $rsm->addfieldresult('bp','id','id');             $query = $this->getdoctrine()->getmanager()->createnativequery('select * bp_department bp_dpt', $rsm);              $result = $query->getresult(); 

but same shit, have no idea.