Entity Framework - Mapping issue

I had the following entities in my domain:

	public class ActiveDirectoryItem
	{
	public int Id { get; set; }
	public int ActiveDirectoryId { get; set; }
	public string Name { get; set; }
	public string Type { get; set; }
	}

view raw ActiveDirectoryItem.cs hosted with ❤ by GitHub

	public class Role
	{
	public int Id { get; set; }
	public string Name { get; set; }
	public string Description { get; set; }
	public virtual ICollection<Task> Tasks { get; set; }
	public virtual ICollection<Operation> Operations { get; set; }
	}

view raw Role.cs hosted with ❤ by GitHub

	public class RoleAssignment
	{
	public int Id { get; set; }
	public Role Role { get; set; }
	public virtual ICollection<ActiveDirectoryItem> ActiveDirectoryItems { get; set; }
	}

view raw RoleAssignment.cs hosted with ❤ by GitHub

And this is how it was mapped through Entity Framework:

	modelBuilder.Entity<RoleAssignment>()
	.HasRequired<Role>(r => r.Role)
	.WithOptional()
	.WillCascadeOnDelete(true);
	modelBuilder.Entity<RoleAssignment>()
	.HasMany<ActiveDirectoryItem>(r => r.ActiveDirectoryItems)
	.WithOptional()
	.WillCascadeOnDelete(true);

view raw ModelBuilder.cs hosted with ❤ by GitHub

Unfortunately Entity Framework got confused when I tried to create a new Role and RoleAssignment. It generated the wrong query for the RoleAssignment and tried to set the “Id” field to the Role id.

To fix it I had to explicitly tell Entity Framework to use the Role_Id column to map the foreign key relationship:

	modelBuilder.Entity<RoleAssignment>()
	.HasRequired<Role>(r => r.Role)
	.WithOptional()
	.Map(a=> a.MapKey("Role_Id"))

view raw ModelBuilder.cs hosted with ❤ by GitHub

Strange thing is that this code was working in a previous release of the application.