public int UpdateQUantity(int id, string name, int quantity) { if (!itemDataAccess.HasThisId(id) || !itemDataAccess.HasThisName(name)) { return(-1); } else { if (itemDataAccess.UpdateQuantity(id, quantity) <= 0) { return(-2); } else { DateTime date = DateTime.Today; double price = itemDataAccess.GetUnitPrice(id); if (transactionDataAccess.HasTransaction(date)) { return(transactionDataAccess.UpdateExpense(date, quantity * price)); } else { return(transactionDataAccess.AddExpense(DateTime.Today, quantity * price, 0)); } } } }