The eXpress Persistent Objects library supports deferred and immediate object deletion. Deferred deletion means that XPO does not physically delete the record in the underlying data store when the corresponding persistent object is deleted. Instead, it marks the record as deleted. This avoids database constraint exceptions when deleting related objects. Deleted objects can be restored later.
Immediate object deletion is an alternative to deferred deletion. The record in the underlying data store is deleted immediately after the object has been deleted. When deleting related objects, you should clear all references to the object and then delete it. Otherwise, you will get an exception.