public DANH_SACH_DICH_VU GetDVByMa(int pMaDV, int pMaHD)
        {
            DANH_SACH_DICH_VU result = new DANH_SACH_DICH_VU();

            result = context.DANH_SACH_DICH_VU.FirstOrDefault(m => m.MA_DICH_VU == pMaDV && m.MA_TOUR_DAT == pMaHD);
            return(result);
        }
        public int Add(DANH_SACH_DICH_VU pDS)
        {
            int result = 0;

            context.DANH_SACH_DICH_VU.Add(pDS);
            result = context.SaveChanges();
            return(result);
        }
        public int Delete(int pMaDV, int pMaTour)
        {
            int result          = 0;
            DANH_SACH_DICH_VU k = context.DANH_SACH_DICH_VU.FirstOrDefault(m => m.MA_DICH_VU == pMaDV && m.MA_TOUR_DAT == pMaTour);

            context.DANH_SACH_DICH_VU.Remove(k);
            result = context.SaveChanges();
            return(result);
        }
        public int Update(DANH_SACH_DICH_VU pDS)
        {
            int result          = 0;
            DANH_SACH_DICH_VU k = context.DANH_SACH_DICH_VU.FirstOrDefault(m => m.MA_DICH_VU == pDS.MA_DICH_VU && m.MA_TOUR_DAT == pDS.MA_TOUR_DAT);

            if (k != null)
            {
                k.SO_LUONG   = pDS.SO_LUONG;
                k.THANH_TIEN = pDS.THANH_TIEN;
            }
            result = context.SaveChanges();
            return(result);
        }