Stackoverflow Question http://stackoverflow.com/questions/34509747/entity-framework-6-hasrequired-and-withmany-partially-working-not-working

Program.cs

using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Linq;

namespace Temp
{
    public class Program
    {
        public static void Main(string[] args)
        {
            using (var ctx = new MyClass())
            {
                ctx.Database.CreateIfNotExists();

                if (!ctx.Companies.Any())
                {
                    var company = ctx.Companies.Create();
                    company.AddUnits();
                    ctx.Companies.Add(company);
                    ctx.SaveChanges();
                }
            }

            using (var ctx = new MyClass())
            {
                var company = ctx.Companies.Find(1);
                Console.WriteLine(company.BusinessUnits?.Count);
            }
        }
    }

    public class Company
    {
        public virtual ICollection<BusinessUnit> BusinessUnits { get; protected set; }

        public int Id { get; protected set; }

        public void AddUnits()
        {
            BusinessUnits = new List<BusinessUnit> { new BusinessUnit(this, "Desc") };
        }
    }

    public class BusinessUnit
    {
        public BusinessUnit()
        {

        }

        public BusinessUnit(Company company, string description)
        {
            Company = company;
            Description = description;
        }

        public int Id { get; protected set; }

        public virtual Company Company { get; protected set; }

        public int CompanyId { get; protected set; }

        public string Description { get; protected set; }
    }

    public class MyClass : DbContext
    {
        public DbSet<Company> Companies { get; set; }
        public DbSet<BusinessUnit> BusinessUnits { get; set; }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            modelBuilder.Entity<BusinessUnit>()
                        .HasRequired(c => c.Company)
                        .WithMany(c => c.BusinessUnits)
                        .HasForeignKey(c => c.CompanyId);
        }
    }
}