EF 6 - Cascade Delete on one to many without backreference

Question

I have something like this:

public class Gadget {
  public int Id { get; set; }
  public string Name { get; set;}
  public int SuperHeroId { get; set; }
}

public class SuperHero {
  public int Id { get; set; }
  public virtual ICollection<Gadget> Gadgets { get; set; }
}

Notice that while a Gadget is "owned" by a Superhero (and therefore there's an FK in the database), my domain model does not have a hard reference in that direction.

When I delete a superhero I would like to also delete all their gadgets. How would I do this?

My research indicates that if I had that reference it would be something like

mapping.Entity<SuperHero>()
  .HasMany(x => x.Gadgets)
  .WithRequired(x => x.SuperHero) //this is the part I can't do
  .WillCascadeOnDelete();

but as noted, that doesn't work with my domain model.

can you not create a hard reference? – Justen Martin Dec 13 '13 at 22:59 — Justen Martin, Dec 13 '13 at 22:59
No - In my case, that would be bad design. – George Mauer Dec 13 '13 at 23:00 — George Mauer, Dec 13 '13 at 23:00

score 15 · Accepted Answer · answered Dec 14 '13 at 13:42

mapping.Entity<SuperHero>()   
       .HasMany(x => x.Gadgets)
       .WithRequired() //use the override that doesn't 
                       //specify a navigation property             
       .WillCascadeOnDelete();

http://msdn.microsoft.com/en-us/library/gg696502(v=vs.113).aspx

Configures the relationship to be optional:required without a navigation property on the other side of the relationship.

EF 6 - Cascade Delete on one to many without backreference

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