I'm getting this error when I'm posting data to my API:

An error occurred while saving the entity changes. See the inner exception for details.
 
---> Microsoft.Data.SqlClient.SqlException (0x80131904): 

The INSERT statement conflicted with the FOREIGN KEY constraint "FK_OrderLine_Order_OrderID". 

The conflict occurred in database "AnimimoMicroservicesNewOrderServiceContext-feca99ec-8feb-4680-b1f5-f1a32825a8c1", table "dbo.Order", column 'OrderID'.

This is the HttpPost method where I'm posting my model to the database:

// POST: api/Orders
        [HttpPost]
        public async Task<ActionResult<Order>> PostOrder(PostOrderDTO postOrderDto)
        {

            var order = new Order(postOrderDto.Identifier, postOrderDto.Customer);

            var json = JsonConvert.SerializeObject(order);

            var content = new StringContent(json, Encoding.UTF8, "application/json");

            _context.Order.Add(order);

            var basket = await GetBasketItems(postOrderDto.Identifier);
            var newOrderId = order.OrderID;

            foreach (var item in basket.Items)
            {
                var orderLine = new OrderLine
                {
                    OrderID = newOrderId,
                    ProductId = item.ProductId,
                    Quantity = item.Quantity
                };

                _context.OrderLine.Add(orderLine);
            };

            await _context.SaveChangesAsync();

            return CreatedAtAction("GetOrder", new { id = order.OrderID }, order);
        }

The 'OrderID' is auto-generated when posting to Order but I need same generated OrderID to be posted and saved in OrderLine as well, here is what my Order database looks like: OrderDB So the OrderID that is generated when I post and save to Order is what I'm trying to get to my OrderLine DB which looks like this in my database: OrderLineDB

It only says NULL, then I tried the following code above in the POST method to post the OrderID but got the error as stated above, I'm trying to resolve this

This is my Order.cs model:

public class Order
    {
        public Order(int orderID, string identifier, string customer)
        {
            OrderID = orderID;
            Identifier = identifier;
            Customer = customer;
        }

        public Order(string identifier, string customer)
        {
            Identifier = identifier;
            Customer = customer;
        }

        [Key]
        public int OrderID { get; set; }
        public string Identifier { get; set; }

        public string Customer { get; set; }

        //[NotMapped]
        public IEnumerable<OrderLine> Items { get; set; } = new List<OrderLine>();
    }

The 'OrderID' in Order.cs model is a foreign key to the OrderLine table which looks like this:

public class OrderLine
    {
        public int Id { get; set; }
        public int OrderID { get; set; }
        public int ProductId { get; set; }
        public int Quantity { get; set; }
    }

How do I fix this? I want the generated OrderID of my Order table to be posted to my OrderLine table with the same Post method but I only got the error as stated above, can I fix this? Thanks for any help in advance

CodePudding user response：

When adding the order you did not save your changes. This means that the order object does not have an id yet. If you save after _context.Order.Add(order); and before adding the id to the orderline this wil be resolved.

CodePudding user response：

you have to fix the navigaion properties

public class OrderLine
    {
        public int Id { get; set; }
       public int Quantity { get; set; }

        public int OrderID { get; set; }
        public int ProductId { get; set; }

         public  virtual Order Order { get; set; }
        public virtual Product { get; set; }
       
    }

and in the code remove _context.Order.Add(order);

            var basket = await GetBasketItems(postOrderDto.Identifier);
  
            foreach (var item in basket.Items)
            {
                var orderLine = new OrderLine
                {
                    Order = order,
                    ProductId = item.ProductId,
                    Quantity = item.Quantity
                };

                _context.OrderLine.Add(orderLine);
            };

            await _context.SaveChangesAsync();

and just because of curiosity, what is this for ?

var json = JsonConvert.SerializeObject(order);
 var content = new StringContent(json, Encoding.UTF8, "application/json");