public function getSubdepartment($con = null)
 {
     if ($this->aSubdepartment === null && $this->subdepartment_id !== null) {
         include_once 'lib/model/om/BaseSubdepartmentPeer.php';
         $this->aSubdepartment = SubdepartmentPeer::retrieveByPK($this->subdepartment_id, $con);
     }
     return $this->aSubdepartment;
 }