public string Update(int itemId, int quantity) { int availablequantity = stockInGateway.GetStockInById(itemId); availablequantity -= quantity; StockIn stockIn = new StockIn(); stockIn.ItemId = itemId; stockIn.AvailableQuantity = availablequantity; int rowAffect = stockInGateway.Update(stockIn); if (rowAffect > 0) { return("Update Successful"); } else { return("Update Failed"); } }