public static void UpdateThamSo(int tuoiToiThieu, int tuoiToiDa, int thoiHanGiaTriThe, int khoangCachNXBToiDa,
                                        int soLuongSachMuonToiDa, int soNgayMuonToiDa, double tienPhat)
        {
            THAMSO ts = db.THAMSOes.SingleOrDefault();

            ts.TuoiToiThieu              = tuoiToiThieu;
            ts.TuoiToiDa                 = tuoiToiDa;
            ts.ThoiHanGiaTriThe          = thoiHanGiaTriThe;
            ts.KhoangCachNamXuatBanToiDa = khoangCachNXBToiDa;
            ts.SoLuongSachMuonToiDa      = soLuongSachMuonToiDa;
            ts.SoNgayMuonToiDa           = soNgayMuonToiDa;
            ts.TienPhat = tienPhat;
            db.SaveChanges();
        }
        public static THAMSO LoadThamSo()
        {
            THAMSO thamso = db.THAMSOes.SingleOrDefault();

            return(thamso);
        }