Navigation Properties as Primary Keys

Question

I'm using EF 6 with MVC 5. I have a class defined as follows:

public class ConEdSignup
{
    [Key, Column(Order = 0)]
    public virtual ApplicationUser Attendee { get; set; }
    [Key, Column(Order = 1)]
    public virtual ConEdSession ConEdSession { get; set; }
    [Required]
    public DateTime SignupTime { get; set; }
    [Required]
    public bool Attended { get; set; }
}

This is basically a link table for a many-to-many relationship where I have additional properties about that relationship. When I try to create a migration for this, it gives me the error "Models.ConEdSignup: : EntityType 'ConEdSignup' has no key defined. Define the key for this EntityType."

I clearly defined the keys for it, but it doesn't like it. How can I use these navigation properties as the primary keys?

score 2 · Answer 1 · answered Jun 22 '14 at 01:03

2

I believe this is because you have chosen the complex entities as they keys. You need to also define the primitives which act as the foreign keys for those entities.

answered Jun 22 '14 at 01:03

TheNorthWes

2,661
19
35

Yes, it does work if I do it that way. I was just hoping to not have to define them, as I don't want the primitives showing up as properties of the class. – Jordan Jun 22 '14 at 03:44
As far as I know you have to. That is how the EF works, and does some of its magic like how it facilitates lazy loading. – TheNorthWes Jun 22 '14 at 05:55

score 0 · Accepted Answer · answered Jun 22 '14 at 07:30

You should read this article on MSDN :-

http://msdn.microsoft.com/en-gb/data/jj679962.aspx

It explains the conventions that Entity Framework adheres too. It also explains how to create you own custom conventions.

You need to setup your classes in a specific way so that EF recognises what your trying to achieve.

Navigation Properties as Primary Keys

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