Parse sort query via pointer

Question

I need to do a simple query sort with Parse.

I have two classes: Captain and Boat. Every Captain has a Boat point

Answer 1

There is a scalable solution for this, with rather minimal overhead: Currently you have a table of boats and a table of captains, where each captain contains a pointer to a boat.

You should add a third table - let'c call it 'captains boats', which contains all the boats that are contained in a captain object. You maintain it by adding the boat when a new captain is added and by removing it from the table when a captain is deleted.

In order to sort the captains by their boats:

1. Query 'CaptainsBoats', sorted by whatever. Notice that even if this table contains a million records, you will get the first X that are relevant to you.

2. Query 'Captains', use the 'containedIn' method with the boat list from step 1: [captainQuery whereKey:"boat" containedIn:boatList].

3. Now you have only the captain objects you need (out of a possible million). Sort them locally according to whatever.