I'm creating a voting system for records I have stored in CloudKit. Each record is stored with a sum of votes. I want each user to only be able to vote on each record once.
Is there a way to query all records of a given type that have not been modified by a given user?
If this isn't possible any clever suggestions for this problem?
I want to avoid storing id's of records on the user record as that would have poor scaling as the user voting activity and total of records goes up.
One option would be to store an array of CKReferences as a property of each record, with the CKReferences pointing to users. You could then query with a predicate something like "user IN votingUserReferences". Not sure how that would scale though.
Another option, probably better, is to have a Vote record type, that has a reference to the user, and a reference to the record. If you construct the record id for these Vote records as a concatenation of the user id and the record id, you should be able to very quickly fetch the vote for a given user and record.
The other advantage of setting the record id for Vote that way is that should you try to create a new Vote when the user has already voted on that record, you will get an error, because a record id has to be unique.
