public void add(List <PayrollPaymentItemsModel> items, PayrollPaymentsModel model)
        {
            if (items.Count == 0)
            {
                return;
            }

            Guid?PayrollPayments_Id = null;

            foreach (PayrollPaymentItemsModel item in items)
            {
                if (item.PayrollPayments_Id != null)
                {
                    PayrollPayments_Id = item.PayrollPayments_Id;
                    break;
                }
            }

            string log = string.Format("Payment of {0:N0} on {1:dd/MM/yy}", model.Amount, model.Timestamp);

            if (!string.IsNullOrWhiteSpace(model.Notes))
            {
                log += ", Notes: " + model.Notes;
            }

            if (PayrollPayments_Id != null)
            {
                log   = "Additional " + log;
                model = get(Session, (Guid)PayrollPayments_Id);
            }
            else
            {
                model.Id = Guid.NewGuid();

                db.Database.ExecuteSqlCommand(@"
	                -- INCREMENT LAST HEX NUMBER
	                DECLARE @HexLength int = 5, @LastHex_String varchar(5), @NewNo varchar(5)
	                SELECT @LastHex_String = ISNULL(MAX(No),'') From PayrollPayments	
	                DECLARE @LastHex_Int int
	                SELECT @LastHex_Int = CONVERT(INT, CONVERT(VARBINARY, REPLICATE('0', LEN(@LastHex_String)%2) + @LastHex_String, 2)) --@LastHex_String length must be even number of digits to convert to int
	                SET @NewNo = RIGHT(CONVERT(NVARCHAR(10), CONVERT(VARBINARY(8), @LastHex_Int + 1), 1),@HexLength)

                INSERT INTO PayrollPayments (Id, No,    Timestamp, UserAccounts_Id, Amount, Branches_Id, Approved, Cancelled, CancelNotes, Notes) 
                                     VALUES(@Id,@NewNo,@Timestamp,@UserAccounts_Id,@Amount,@Branches_Id,@Approved,@Cancelled,@CancelNotes,@Notes);
            ",
                                              DBConnection.getSqlParameter(PayrollPaymentsModel.COL_Id.Name, model.Id),
                                              DBConnection.getSqlParameter(PayrollPaymentsModel.COL_Timestamp.Name, model.Timestamp),
                                              DBConnection.getSqlParameter(PayrollPaymentsModel.COL_No.Name, model.No),
                                              DBConnection.getSqlParameter(PayrollPaymentsModel.COL_UserAccounts_Id.Name, model.UserAccounts_Id),
                                              DBConnection.getSqlParameter(PayrollPaymentsModel.COL_Amount.Name, model.Amount),
                                              DBConnection.getSqlParameter(PayrollPaymentsModel.COL_Branches_Id.Name, model.Branches_Id),
                                              DBConnection.getSqlParameter(PayrollPaymentsModel.COL_Approved.Name, model.Approved),
                                              DBConnection.getSqlParameter(PayrollPaymentsModel.COL_Cancelled.Name, model.Cancelled),
                                              DBConnection.getSqlParameter(PayrollPaymentsModel.COL_CancelNotes.Name, model.CancelNotes),
                                              DBConnection.getSqlParameter(PayrollPaymentsModel.COL_Notes.Name, model.Notes)
                                              );
            }
            ActivityLogsController.Add(db, Session, model.Id, log);

            PayrollPaymentItemsController.update_PayrollPayments_Id(db, Session, model.Id, items);

            db.SaveChanges();
        }