protected function _update(Model_DomainObjectAbstract $obj)
 {
     $db = $this->getDb();
     $data = array('name' => $obj->getName(), 'path' => $obj->getPath(), 'users_id' => $obj->getUsersId());
     $where = $db->quoteInto('id = ?', $obj->getId());
     $db->update('catalogs', $data, $where);
 }