gistfile1.cs

 public class PersonMap : EntityTypeConfiguration<Person>
    {
        public PersonMap()
        {
            this.ToTable("Person");
        }
    }

    public class PersonWithPreferenceMap : PersonMap 
    {
        public PersonWithPreferenceMap()
        {
            // Primary Key
            this.HasKey(t => t.UserName);

            // Relationships
            this.HasMany(t => t.Preferences)
                .WithRequired()
                .HasForeignKey(t => t.Username);

            this.Ignore(t => t.Orders);
        }
    }

    public class PersonWithOrderMap : PersonMap
    {
        public PersonWithOrderMap()
        {
            // Primary Key
            this.HasKey(t => t.PersonId);

            // Relationships
            this.HasMany(t => t.Orders)
                .WithRequired()
                .HasForeignKey(t => t.PersonId);

            this.Ignore(t => t.Preferences);
        }
    }