What is the right way to delete all of the collection items of an EF entity? In the code below, DocumentItems is the collection of related document items for a document. This code proceedes on Clear() but fails on SaveChanges() because related items are connected to their document via FK and FK is mandatory. So I guess they somehow remain floating up in the air without a foreign key after Clear().
Do I solve this with a foreach loop over the collection calling Remove() on each item or is there another way?
// remove existing document items to prepare for refreshing them
existing.DocumentItems.Clear();
// adds new Document Items
PrepareInvoice(existing, collection);
_repository.SaveChanges();