CODEWITHSUNDEEP
entity-frameworkentity-framework-4
Bick
Bick

Reputation: 18521

Entity Framework - deleting N:N relation

I have the following class

public class ObjectA{
   private List<ObjectB> list;    
}

ObjectA and ObjectB are in N:N relation.

I want to delete only the relation and I use

 while (objectA.list.Any())
        objectA.list.Remove(objectA.list.First());

And I get

The operation failed: The relationship could not be changed because one or more of the foreign-key properties is non-nullable. When a change is made to a relationship, the related foreign-key property is set to a null value. If the foreign-key does not support null values, a new relationship must be defined, the foreign-key property must be assigned another non-null value, or the unrelated object must be deleted.

EDIT: updating model definition
There are three tables in my model :
* ClassA - SchemaA,
* ClassAClassB - SchemaA,
* ClassB - SchemaB,

In my contex (and edmx ) I have only Schema A ( ClassA and ClassAClassB)
There for it is 1:N to the relation Table.

Here is the code generated from the edmx.

public partial class ClassA:DomainEntity
{
    ....
    public virtual ICollection<ClassB>  ClassAClassB { get; set; }
}

What am I doing wrong?

Thanks.

Upvotes: 1

Views: 451

Answers (1)

Ladislav Mrnka
Ladislav Mrnka

Reputation: 364249

If you have one-to-many relation with non-nullable FK you must also delete ObjectB because removing it from navigation property will only remove the relation (makes FK null) but does not remove the ObjectB itself. Try this:

 while (objectA.list.Any()) {
     var b = b;
     objectA.list.Remove(b);
     entities.DeleteObject(b);    
 }

Upvotes: 1

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