问当实体框架6中不需要声明关系时？

EN

[Table("item")]
public class Item
{
    public Item()
    {
        ItemNotes = new HashSet<ItemNote>();
    }
    [Key]
    [Column("itemID", TypeName = "int")]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int itemID { get; set; }

    public ICollection<ItemNote> ItemNotes { get; set; }
}

[Table("itemNotes")]
public class ItemNote
{
    [Key]
    [Column("id", TypeName = "int")]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int Id { get; set; }
    [Column("itemID", TypeName = "int")]
    public int ItemId { get; set; }
    [Column("note", TypeName = "varchar")]
    [MaxLength(255)]
    public string Note { get; set; }
}    

public class MyContext : DbContext
{
    public MyContext()
        : base("name=MyContext")
    {
    }
    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        Database.SetInitializer<MyContext>(null);

        //I removed this relationship:
        //modelBuilder.Entity<Item>().HasMany(i => i.ItemNotes).WithRequired().HasForeignKey(i => i.ItemId);

        base.OnModelCreating(modelBuilder);
    }    
}

    [TestCase]
    public void QueryItemWithItemNotesTest()
    {
        FniContext fniContext = new FniContext();

        int itemId = fniContext.Database.SqlQuery<int>("SELECT TOP(1) itemId FROM item WHERE itemId IN (SELECT itemId FROM dbo.itemNotes)").FirstOrDefault();
        var item = fniContext.Items.AsNoTracking()
            .Include(i => i.ItemNotes)
            .Where(i => i.itemID == itemId).FirstOrDefault();

        Assert.IsNotNull(item);
        Assert.Greater(item.ItemNotes.Count, 0);
    }