Add a "set to null" delete action

[megafetis]

Set(p => p.SomeCollectionItems, m =>
            {
                m.Lazy(CollectionLazy.Lazy);
                m.Key(km =>
                {
                    km.ForeignKey("foregn_key_fk");
                    km.OnDelete(OnDeleteAction.Cascade); // how to: OnDeleteAction.SetToNull
                });
                m.Table("table_of_items");
            }, om => om.OneToMany(p => p.Class(typeof(ItemClass))));

It is usefull for schema action and generate schema with foregn keys with cascade action "SetToNull"

[fredericDelaporte]

It seems to me you are asking for a feature that does not exist at all in NHibernate, not just a thing that would be lacking in mapping by code while being available in xml mappings. Am I wrong?

[megafetis]

Yes, I am asking a new feature, include it to next version, if it possible