protected function add(WebsiteOpinion $websiteOpinion)
 {
     $q = $this->dao->prepare('INSERT INTO ' . $this->table() . ' SET USERNAME = :username, COMMENT = :comment');
     $q->bindValue(':username', $websiteOpinion->getUsername());
     $q->bindValue(':comment', $websiteOpinion->getComment());
     $q->execute();
     $websiteOpinion->setId($this->dao->lastInsertId());
 }