Delete related elements in 1:N relation and not only inserts null in the foreign key

Question

I have the following class

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

ObjectA and ObjectB are in 1:N relation.

I want to delete some of ObjectB instances and I use:

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

List is of the relation table -
```
List<ObjectAobjectB>
```

In the Database I have defined therelation as a nullable foreign key otherwise 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.

So now that it is Nullable foreign key,
When I run sql profiling I get the following:

exec sp_executesql N'update [Schem].[ClassB]
set [ClassAID] = null
where ([Id] = @0)
',N'@0 uniqueidentifier',@0='092CE959-370A-4785-AF4A-93A0E4952C59'

It just enters a null in the relation instead of deleting the object.
What am I doing wrong?

Thanks.

You're only removing the relationship, you have to delete ObjectB from the context as well like such: context.Set<ObjectB>().Remove(objectBInstance); — Quinton Bernhardt

Britton Britton · Accepted Answer · 2013-01-19T01:10:00

objectA.list.Remove(objectA.list.First()); is removing the relationship, not the actual entity. If you want to delete the objectB's from the database then you have to remove them from the context like so:

foreach(var item in objectA.list.ToList())
    context.ObjectBs.Remove(item);

Delete related elements in 1:N relation and not only inserts null in the foreign key

2 Answers