public function getCommerce($force = false)
    {
        if ($this->nb_commerce === null || $force) {
            $this->nb_commerce = null;
            if (!$this->isBuiltIn() && $this->isValueNumeric(NABU_COMMERCE_FIELD_ID)) {
                $nb_commerce = new CNabuCommerce($this->getValue(NABU_COMMERCE_FIELD_ID));
                if ($nb_commerce->isFetched()) {
                    $this->nb_commerce = $nb_commerce;
                }
            }
        }

        return $this->nb_commerce;
    }