How do I fetch all CloudKit Records created by the current user?

Question

Say I have a 'Species' Record Type that contains Public Records which were created by a number of Users. Currently, my query retrieves all records of 'Species':

private func fetchSpecies() {
    // Fetch Public Database
    let publicDatabase = CKContainer.defaultContainer().publicCloudDatabase

    // Initialize Query
    let query = CKQuery(recordType: "Species", predicate: NSPredicate(format: "TRUEPREDICATE"))

    // Configure Query
    query.sortDescriptors = [NSSortDescriptor(key: "latinName", ascending: true)]

    // Perform Query
    publicDatabase.performQuery(query, inZoneWithID: nil) { (records, error) -> Void in
    dispatch_async(dispatch_get_main_queue(), { () -> Void in
        // Process Response on Main Thread
        self.processResponseForQuery(records, error: error)
        })
    }
}

How can I only fetch records that were created by the current user (as in the owner of the device)?

Thank you!

Answer 1

Each CKRecord has a creatorUserRecordID property; therefore, you can try to get owner's userRecordID first. Then, have it into NSPredicate.

let container: CKContainer = CKContainer.defaultContainer()
let completionHandler: (CKRecordID?, NSError?) -> Void = { (userRecordID: CKRecordID?, error: NSError?) in
    if let userRecordID = userRecordID {
        let predicate = NSPredicate(format: "creatorUserRecordID == %@", userRecordID)
        let query = CKQuery(recordType: "Species", predicate: predicate)
        query.sortDescriptors = [NSSortDescriptor(key: "latinName", ascending: true)]
        container.publicCloudDatabase.performQuery(query, inZoneWithID: nil) { (records, error) -> Void in

        }
    }
}
//// Returns the user record ID associated with the current user.
container.fetchUserRecordIDWithCompletionHandler(completionHandler)

Answer 2

I also posted on the Apple Developer Forums, and I was provided with an excellent solution:

To fetch only a specific user records, you need to create a CKReference pointing to that user id (recordID), then use a predicate on that. It looks like this:

First fetch the user record id

yourContainer.fetchUserRecordIDWithCompletionHandler { (userID, error) -> Void in  
    if let userID = userID {  
        // here's your userID (recordID) to play with  
    }  
}

Then construct the predicate:

let reference = CKReference(recordID: userID, action: .None)  
let predicate = NSPredicate(format: "creatorUserRecordID == %@", reference)  
let query = CKQuery(recordType: "Species", predicate: predicate) 

And then use the query as normal.

Happy fetching!