Seems pretty awesome if you have actually taken care of all of the backbone sync backend, so you can just use all of the collection create, update, findAll and everything and it just reads from or updates the database?

How do you handle a situation with relationships where you need to specify "give me all of the objects from collection X where parentId is YYYYY"?

Also how do you handle sort of arbitrary queries?

I was thinking about making a service like this because everyone wants to use Backbone.js.