Entity Framework One-to-One Relationship

Data.cs

 public class DataContext : DbContext
    {
        public DbSet<Order> Orders { get; set; }
        public DbSet<OrderDetail> OrderDetails { get; set; }
    }

    public class Order
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public virtual OrderDetail Detail { get; set; }
    }

    public class OrderDetail
    {
        [Key]
        [ForeignKey("Order")] //[ForeignKey] required for 1:1
        public int OrderId { get; set; }

        public Order Order { get; set; }  //Navigation property required for 1:1
       
        public string ReferenceNumber { get; set; } 
    }