How to map in EF Core a collection of child entities when children has not ID of the parent?

Question

I have this:

Class Order
{
    long ID;
    ...
}

Class Item
{
    long Id;
    IdProduct;
    decimal Amount;
    ...
}

How could I map this in EF Core using fluent API? Or is it not possible and I have to have in the childs a property for the ID of the parent? But in my case, from a point of view of DDD I don't need this property in the children because the children has not need to know about the parent.

Thanks.

Answer 1

Assuming you have a collection of 'Item' in Order ...

class Order
{
    public long ID { get; set; }
    public List<Item> Items { get; set; }
}

Order Config:

builder.HasMany<Item>(p => p.Items)
   .WithOne()
   .HasForeignKey("OrderId");

This will create FK property OrderId on the Item without it being explicitly declared in the class itself.