How do I use LINQ-to-Entities to insert data into a specific table?

Question

Question: what is the LINQ-to-Entity code to insert an order for a specific customer?

Answer 1

L2E does not support set-based operations currently (update without select). See Use linq to generate direct update without select

Answer 2

Your code isn't far off. Just change your second line to read as follows:

Customer customer = ctx.Customer.FirstOrDefault(c => c.FirstName == "Bobby");
if (customer != null)
{
    //...

Just replace the c.FirstName == "Bobby" with something that can strongly identify the customer you're looking for (e.g. c.Id == customerID if you already know what the ID is).

Answer 3

Notice that Order has a Customer property. You don't have to add the Order to the Customer -- you can do it the other way around. So, instead of creating a new Customer, get the Customer using Linq, then add it to your new Order.

using (OrderDatabase ctx = new OrderDatabase())
{
    ctx.AddOrder(new Order()
    {
        OrderQuantity = 2,
        OrderDescription = "Widgets",
        Customer = ctx.Customers.First<Customer>(c => c.CustomerId == yourId)
    });
    ctx.SaveChanges();
}

Answer 4

I don't get what the problem is, exactly.

var mycustomer = context.Customers.Where(x => x.id == 100).FirstOrDefault();
if(mycustomer != null)
{
  mycustomer.Orders.Add(myorder); 
}
context.SaveChanges();