You are right about the [cd], which is not supposed to be here, blame it on poor copy-paste skills.
So how can I fix the predicate to compare entities? - Koen. > On Mar 1, 2014, at 10:22 AM, Sixten Otto <[email protected]> wrote: > > Two things: > > 1. No, doing a string comparison with contains (and case and diacritical > folding active) is one of the slower kinds of string comparison. Straight > equality should be much faster. > > 2. You say that there are two entities, with a relationship defined. Why, > then, are you doing a string comparison in this predicate? Checking the value > of the relationship should be much faster. > > Sixten > > >> On Sat, Mar 1, 2014 at 5:22 AM, Koen van der Drift >> <[email protected]> wrote: >> Consider two entities in a many-to-many relationship: Library and Book. In a >> NSFetchResultController backed UITableView, I like to show all the books >> from one library, so I constructed the following fetch request: >> >> NSFetchRequest *fetchRequest = [NSFetchRequest >> fetchRequestWithEntityName: @"Book"]; >> NSSortDescriptor *sort = [[NSSortDescriptor alloc] initWithKey: @"date" >> ascending: YES]; >> [fetchRequest setSortDescriptors: @[sort]]; >> >> NSPredicate *predicate = [NSPredicate predicateWithFormat: @"libraries >> contains[cd] %@", self.library]; >> [fetchRequest setPredicate: predicate]; >> >> which is then fed into the NSFetchedResultController when the view opens. >> >> There is a noticeable delay of a few 100 ms when the view opens, and I >> suspect that the predicate I have is not optimal by using 'contains'. >> >> Is there a way to improve on this? >> >> Thanks, >> >> - Koen. >> >> >> _______________________________________________ >> >> Cocoa-dev mailing list ([email protected]) >> >> Please do not post admin requests or moderator comments to the list. >> Contact the moderators at cocoa-dev-admins(at)lists.apple.com >> >> Help/Unsubscribe/Update your Subscription: >> https://lists.apple.com/mailman/options/cocoa-dev/himself%40sfko.com >> >> This email sent to [email protected] > _______________________________________________ Cocoa-dev mailing list ([email protected]) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [email protected]
