Schema specified is not valid. Errors: The relationship was not loaded because the type is not available

Question

I wish to reference the OrderAddress model twice in my Order model; once as a ShippingAddress and once as a Billing

Answer 1

You need to change your OrderAddress entity and your Fluent API mappings to the following:

OrderAddress:

public class OrderAddress : BaseModel
{
    ...
    public virtual ICollection BillingOrders { get; set; }
    public virtual ICollection ShippingOrders { get; set; }
    ...
}

Fluent API:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    base.OnModelCreating(modelBuilder);

    modelBuilder.Entity()
                .HasRequired(m => m.ShippingAddress)
                .WithMany(t => t.ShippingOrders)
                .HasForeignKey(m => m.ShippingAddressId)
                .WillCascadeOnDelete(false);

    modelBuilder.Entity()
                .HasRequired(m => m.BillingAddress)
                .WithMany(t => t.BillingOrders)
                .HasForeignKey(m => m.BillingAddressId)
                .WillCascadeOnDelete(false);
}

Check this SO post for more, it is about the same problem as yours.