Zend FR

public function addPrevision($id_commande = 0, $nb_prevision = 1)
    {
        if ($id_commande >0 && is_int($nb_prevision))
        {
            $rowset = $this->find($id_commande);  //-- faisant référe
            if($rowset->count() >0)
            {
                $row = $rowset->current();
                $row->NB_PREVISION = $row->NB_PREVISION + $nb_prevision;
                $row->save();
            }
        }
    }