POCO self referencing many to many

Question

It is look like same question but mine little bit different.

Entity Framework 4 CTP 5 Self Referencing Many-to-Many

sample code;

public class Category 
{
    [Key]
    public int Id { get; set; }

    public string Name { get; set; }

    public virtual ICollection<Category> Parents { get; set; }
    public virtual ICollection<Category> Children { get; set; }        
}

I got right result when I define a field Parent as Category, instead of parents as List.

Category class well designed, but POCO? What should I do? Thanks in advance.

What problem do you have exactly? And are you really still using CTP5? It's outdated and you should update to EF 4.1 (http://blogs.msdn.com/b/adonet/archive/2011/04/11/ef-4-1-released.aspx) — Slauma, Apr 20 '11 at 17:15
But what doesn't work? If I try your model with EF 4.1 I get many-to-many mapping with one single join table. I looks correct to me. I cannot see the problem. — Slauma, Apr 21 '11 at 14:41
@Yablargo it will be like this public virtual Category Parent { get; set; } — Nuri YILMAZ, Jul 20 '11 at 17:34

score 2 · Accepted Answer · answered Apr 21 '11 at 14:40

Your class works fine for me without any customizations. Even the [Key] attribute is not required.

Here's some code that exercises this model:

using (var context = new MyContext())
{
    var parent1 = new Category { Name = "Parent 1" };
    var parent2 = new Category { Name = "Parent 2" };
    var child1 = new Category { Name = "Child 1" };
    var child2 = new Category { Name = "Child 2" };
    parent1.Children = new List<Category> { child1, child2 };
    parent2.Children = new List<Category> { child1, child2 };
    context.Categories.Add(parent1);
    context.Categories.Add(parent2);
    context.SaveChanges();
}
using (var context = new MyContext())
{
    var categories = context.Categories.OrderByDescending(x => x.Children.Count)
                                       .ToList();
    foreach (var category in categories)
    {
        Console.Write(category.Name + ": ");
        Console.WriteLine("Parents ({0}) Children ({1})",
            string.Join(",", category.Parents.Select(x => x.Name).ToArray()),
            string.Join(",", category.Children.Select(x => x.Name).ToArray()));
    }
}

This will print:

Parent 1: Parents () Children (Child 1,Child 2)
Parent 2: Parents () Children (Child 1,Child 2)
Child 1: Parents (Parent 1,Parent 2) Children ()
Child 2: Parents (Parent 1,Parent 2) Children ()

thanks a lot. it is working. I made mistake when I checked Sql Server. I will never look at it again :) — Nuri YILMAZ, Apr 22 '11 at 08:28

POCO self referencing many to many

1 Answers1