public function Save($giohang) {
        $check = TRUE;
        $id = "";
        $this->db->trans_begin();
        $data = array(
            "mahd" => $this->mahd,
            "matk" => $this->matk,
            "ngaydat" => $this->ngaydat,
            "sodt" => $this->sodt,
            "tennn" => $this->tennn,
            "diachi" => $this->diachi,
            "mahinhthuctt" => $this->mahinhthuctt,
            "matrangthai" => $this->matrangthai
        );
        $isTrue = $this->db->insert("hoadon", $data);
        if ($isTrue)
            foreach ($giohang as $item) {
                $masp = $item['id'];
                $soluong = $item['qty'];
                $giaban = $item['price'];

                if ($this->SoLuongSPCon($masp) < $soluong) {
                    $check = FALSE;
                    $id = $masp;
                    break;
                } else {
                    $sql = "INSERT INTO ct_hoadon(mahd, masp, sl, giaban) values (?,?,?,?)";
                    $this->db->query($sql, array("$this->mahd", "$masp", $soluong, $giaban));
                    $sql = "update sanpham set soluong=soluong-? where masp=?";
                    $this->db->query($sql, array($soluong, "$masp"));
                }
                // echo $this->db->last_query();
            }
        if ($this->db->trans_status() === FALSE || $check == FALSE) {
            $this->db->trans_rollback();
            return array("result" => FALSE, 'masp' => $id);
        } else {
            $this->db->trans_commit();
            return array("result" => TRUE);
        }


        //return $isTrue;
    }