Proper implementation of an Identifying relationship in Entity Framework?

问题

Let's say I have an entity Author which has a name can write 0 .. 1 .. or many of the entity Book. The Book must be written by one Author, and it is not meaningful to talk of a Book with no Author.

This (I believe) would be classified as an identifying relationship. With the EntityTypeConfiguration, would the following be the correct way of implementing this identifying relationship?

public BookMapping()
{
    HasRequired(book => book.Author)
   .WithMany(author => author.Books)
   .HasForeignKey(book => book.AuthorID);
}

回答1:

It is not identifying relation. It is just common one-to-many relation. To make it identifying you must also map composite primary key consisting of BookID and AuthorID.

HasKey(book => new { book.BookID, book.AuthorID });

来源：https://stackoverflow.com/questions/9579602/proper-implementation-of-an-identifying-relationship-in-entity-framework