multiple "1 to 0..1" relationship models - asp.net-mvc

Question

I am using this tutorial from microsoft to create a one-zero-to-one relationship with EF4.1 Between an Instructor and OfficeAssignment. This is working like a charm.
But now I want to add a Home for each Instructor (1 to zero-or-1) like in this:
I added the Home model exactly the same way as the OfficeAssignment (like in the tutorial above), but when I try to add controllers for these model, I get the error "An item with the same name has already been added".
So my model is set up incorrectly.
What is wrong with the below?
How do I create multiple one-to-zero-to-one relationships in EF4.1?
public class Instructor
{
public Int32 InstructorID { get; set; }
public string LastName { get; set; }
public string FirstMidName { get; set; }
public virtual OfficeAssignment OfficeAssignment { get; set; }
public virtual Home Home { get; set; }
}
public class OfficeAssignment
{
[Key]
public int InstructorID { get; set; }
public string Location { get; set; }
public virtual Instructor Instructor { get; set; }
}
public class Home
{
[Key]
public int InstructorID { get; set; }
public string Location { get; set; }
public virtual Instructor Instructor { get; set; }
}
public class Context : DbContext
{
public DbSet<OfficeAssignment> OfficeAssignments { get; set; }
public DbSet<Instructor> Instructors { get; set; }
public DbSet<Home> Homes { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
modelBuilder.Entity<Instructor>()
.HasOptional(p => p.OfficeAssignment)
.WithRequired(p => p.Instructor);
modelBuilder.Entity<Instructor>()
.HasOptional(p => p.Home).WithRequired(p => p.Instructor);
}

Answer 1

Doesn't look like EF supports real 1 to 0..1 relationship. You need a foreign key. And add the optional (int?) into the main model.
So I did this as follow, and it works like a charm.
public class Instructor
{
public Int InstructorID { get; set; }
public string LastName { get; set; }
public string FirstMidName { get; set; }
public int? OfficeAssignmentID { get; set; }
public virtual OfficeAssignment OfficeAssignment { get; set; }
public int? HomeID { get; set; }
public virtual Home Home { get; set; }
}
public class OfficeAssignment
{
public int OfficeAssignmentID { get; set; }
public string Location { get; set; }
}
public class Home
{
public int HomeID { get; set; }
public string Location { get; set; }
}