EF: Create/Remove relation from Many-to-Many relations when `AutoDetectChangesEnabled` and `ProxyCreationEnabled` are disabled on DbContext

Question

1. Knowning Foo.Id and Bar.Id how can I create their relation without loading the entities from the DB.

   class Foo {
       public in         
   
   
           

Answer 1

If I'm understanding correctly, you wanted to add Bar object to an existing Foo entity without making a lookup for Foo entity.

Let say, you have Foo (id = 1) already exists. Wanted to add new Bar (id = 100) entity to it.

using (var context = new Context())
{
    var bar = new Bar() { Id = 100 };
    var foo = new Foo() { Id = 1 }; // Only ID is required

    context.Foos.Attach(foo);
    bar.Foos.Add(foo);

    context.Bars.Add(bar);
    context.SaveChanges();
}