Why a child object clears a reference to a parent object when being deleted?

When you call the Delete method, Session does several essential changes on the object to prepare it for deletion. For instance, Session updates links between objects. If the object to be deleted has a reference property decorated with the Association attribute, Session removes that object from the associated collection. When an object is removed from an associated collection, the collection clears the corresponding reference property on the removed object.

The solution that Robert Futch suggested breaks the synchronization of associations and can lead to undesirable consequences. For example, if you delete an object in NestedUnitOfWork and save changes, that object will not be removed from the associated collection in the parent Session.

Currently, XPO does not have an API to restore deleted objects completely. The Deferred Deletion feature is intended for another purpose - avoid conflicts with complex foreign key constraints when deleting multiple objects simultaneously.

I will be very grateful if you tell us about your task, which requires restoring deleted objects. I will try to find the most suitable solution for you.