/**
  * delete session and all related data
  *
  * @access public
  * @return bool
  */
 public function delete()
 {
     global $ilDB;
     global $ilAppEventHandler;
     if (!parent::delete()) {
         return false;
     }
     $query = "DELETE FROM event " . "WHERE obj_id = " . $this->db->quote($this->getId(), 'integer') . " ";
     $res = $ilDB->manipulate($query);
     include_once './Modules/Session/classes/class.ilSessionAppointment.php';
     ilSessionAppointment::_deleteBySession($this->getId());
     include_once './Modules/Session/classes/class.ilEventItems.php';
     ilEventItems::_delete($this->getId());
     include_once './Modules/Session/classes/class.ilEventParticipants.php';
     ilEventParticipants::_deleteByEvent($this->getId());
     foreach ($this->getFiles() as $file) {
         $file->delete();
     }
     $ilAppEventHandler->raise('Modules/Session', 'delete', array('object' => $this, 'obj_id' => $this->getId(), 'appointments' => $this->prepareCalendarAppointments('delete')));
     return true;
 }