protected function modify(ContactRequest $contactRequest)
 {
     $q = $this->dao->prepare('UPDATE ' . $this->table() . ' SET USER_ID_TO = :userIdTo, USER_ID_FROM = :userIdFrom, CONTACT_GROUP_ID = :contactGroupId WHERE ID=:id');
     $q->bindValue(':userIdTo', $contactRequest->getUserIdTo(), PDO::PARAM_INT);
     $q->bindValue(':userIdFrom', $contactRequest->getUserIdFrom(), PDO::PARAM_INT);
     $q->bindValue(':contactGroupId', $contactRequest->getContactGroupId(), PDO::PARAM_INT);
     $q->bindValue(':id', $contactRequest->id(), PDO::PARAM_INT);
     $q->execute();
     $contactRequest->setId($this->dao->lastInsertId());
 }