You might have noted that update and delete operations work thanks to the rowid field, for instance, in the update_contact method from the ContactsController class:

    def update_contact(self):
        if not self.selection:
            return
        rowid = self.contacts[self.selection].rowid
        update_contact = self.view.get_details()
        update_contact.rowid = rowid

Since this is an implementation detail for our SQLite database, this should be hidden from the rest of our components.

A solution would be to add another field to the Contact class with a name such as id or contact_id—note that id is also a Python built-in function and some editors might incorrectly highlight it.

Then, we can assume this field is part of our domain data as a unique identifier and leave the implementation details of how it is generated to the model.