Update/insert in new Android contacts API

When adding a contact in the new android contacts API, can I use newAssertQuery() also for insert, or will it only update an existing entry. If so, what is the difference between newAssertQuery() and newUpdate()?

More generally, do I need to check whether a raw contact or data exist first and then either insert or update, or is there a simp开发者_如何学Pythonler way?