Entity Framework the use of reference

I use

p.AuthorsReference.EntityKey = new System.Data.EntityKey("PetitionsContainer.Authors", "Id", authorId);

but I get entities in PetitionsContainer.Questions participate in 开发者_开发问答the QuestionAuthor relationship.

0 related 'Author' were found. 1 'Author' is expected.

Now, the Author with the Id authorId is already in the database.

It is true that each question must have 1 author.

Though, can't I use AuthorsReference instead of something like p.Authors.Add(new Author())?

If you set up the reference you must also fill the author. You can try using this:

// Attach a dummy author to the context so that context believes that you
// loaded the author from the database
Author a = new Author { Id = authorId };
context.Authors.Attach(a);
// Now assign existing author to the question
question.Author = a;