CODEWITHSUNDEEP
objective-cioscore-datanspredicatekey-value-coding
Arseniy Banayev
Arseniy Banayev

Reputation: 694

CoreData fetch request - complex predicate

How would I simplify this using (ideally) a single predicate with key-value coding collection operators? (The array of interest in the end is filteredGames.)

NSManagedObjectContext *context;
NSFetchRequest *request = [[NSFetchRequest alloc] init];
[request setEntity:[NSEntityDescription entityForName:@"Game" inManagedObjectContext:context];
NSArray *games = [context executeFetchRequest:request error:nil];

NSMutableArray *filteredGames = [[NSMutableArray alloc] init];
for (Game *game in games) {
    NSInteger maxRoundNumber = [game.rounds valueForKeyPath:@"@max.number"];
    Round *maxRound = [[game.rounds filteredSetUsingPredicate:[NSPredicate predicateWithFormat:@"number = %d", maxRoundNumber]] anyObject];
    if (maxRound.someBoolProperty)
        [filteredGames addObject:game];
}

Game has an NSSet property rounds of Rounds, and Round has an NSInteger property number, and I'm looking for those Games whose highest-number Round has some BOOL property someBoolProperty.

Upvotes: 1

Views: 510

Answers (1)

Martin R
Martin R

Reputation: 539685

This seems to do what you want:

NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Game"];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"ANY SUBQUERY(rounds, $r, $r.someBoolProperty = YES).number = @max.rounds.number"];

Upvotes: 2

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