Question

I have a question about defining Foreign Key in EF Code First Fluent API.
I have a scenario like this:

Two class Person and Car. In my scenario Car can have assign Person or not (one or zero relationship).
Code:

    public class Person
{
    public int Id { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
}

public class Car
{
    public int Id { get; set; }
    public string Name { get; set; }
    public Person Person { get; set; }
    public int? PPPPP { get; set; }
}

class TestContext : DbContext
{
    public DbSet<Person> Persons { get; set; }
    public DbSet<Car> Cars { get; set; }

    public TestContext(string connectionString) : base(connectionString)
    {
    }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Car>()
                    .HasOptional(x => x.Person)
                    .WithMany()
                    .HasForeignKey(x => x.PPPPP)
                    .WillCascadeOnDelete(true);

        base.OnModelCreating(modelBuilder);
    }
}

In my sample I want to rename foreign key PersonId to PPPPP. In my mapping I say:

modelBuilder.Entity<Car>()
            .HasOptional(x => x.Person)
            .WithMany()
            .HasForeignKey(x => x.PPPPP)
            .WillCascadeOnDelete(true);

But my relationship is one to zero and I’m afraid I do mistake using WithMany method, but EF generate database with proper mappings, and everything works well.

Please say if I’m wrong in my Fluent API code or it’s good way to do like now is done.

Thanks for help.

Answer 1

I do not see a problem with the use of fluent API here. If you do not want the collection navigational property(ie: Cars) on the Person class you can use the argument less WithMany method.