Entity Framework 4.1 Code First: Single column foreign-key to multiple entities

I've been trying to create model in EF 4.1 to represent a database schema with a single table and column holding foreign keys from two other tables, but have had little luck with both annotations and the fluent API. A sample model is shown here:

public class User
{
    ...
    public virtual ExtendedAttribute ExtendedAttributes { get; set; }
}    

public class Account
{
    ...
    public virtual ExtendedAttribute ExtendedAttributes { get; set; }
}

public class ExtendedAttribute
{
    public Guid Id {get; set;}
    public Guid ItemId {get; set;} // both Account.Id and User.Id stored here
    public string Value { get; set; }
}

开发者_如何学编程

Currently the configuration for these entities looks something like this for both User and Account modelBuilders:

this.HasOptional(u => u.ExtendedAttributes).WithRequired();

Any thoughts on how to do achieve? Many thanks.

---

It is even not possible with the database itself and EF will not put any abstraction for that. You must have separate column and navigation property for each entity.