Core Data NSFetchedResultsController: Error when debugging on device (Unable to generate SQL for predicate)

Question

i have a weird exeption when i debug my app on my device. debugging in simulator works as expected.

i use core data for storing my data
relationships in model are as follows: Location <-> LocationDetails ->> HappyHour
i use NSFetchedResultsController to populate a UITableView
i'm also pretty new to objective-c develpoment

i need to have a SUBQUERY to get to the attributes of the HappyHour entity.

Like this:

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"(0 != SUBQUERY(details.%K, $hh, ($hh.startTime < %@) AND ($hh.endTime > %@)).@count)", weekdayString, theDate, theDate];

ONLY on the DEVICE i get this error/exeption:

* Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Unable to generate SQL for predicate (0 != SUBQUERY(details.hh_montag, $hh, $hh.startTime < CAST(316482000.000000, "NSDate") AND $hh.endTime > CAST(316482000.000000, "NSDate")).@count) (problem on RHS)'

0 CoreFoundation 0x32cf964f __exceptionPreprocess + 114
1 libobjc.A.dylib 0x3313cc5d objc_exception_throw + 24
2 CoreData 0x3228a829 -[NSSQLGenerator newSQLStatementForFetchRequest:ignoreInheritance:countOnly:nestingLevel:] + 688
3 CoreData 0x3228a2eb -[NSSQLAdapter _newSelectStatementWithFetchRequest:ignoreInheritance:] + 378
4 CoreData 0x3228a169 -[NSSQLAdapter newSelectStatementWithFetchRequest:] + 16
5 CoreData 0x3228a005 -[NSSQLCore newRowsForFetchPlan:] + 288
6 CoreData 0x322892c5 -[NSSQLCore objectsForFetchRequest:inContext:] + 420
7 CoreData 0x32288875 -[NSSQLCore executeRequest:withContext:error:] + 304
8 CoreData 0x32287dd5 -[NSPersistentStoreCoordinator executeRequest:withContext:error:] + 896
9 CoreData 0x3228669f -[NSManagedObjectContext executeFetchRequest:error:] + 374
10 CoreData 0x322b9d7f -[NSFetchedResultsController performFetch:] + 766
11 HappyHourRadar 0x0003e723 -[ResultViewController viewDidLoad] + 86
...
terminate called after throwing an instance of 'NSException' Signal received: SIGABRT (Aborted)

Process finished with exit code -1

At [ResultViewController viewDidLoad] +86

i call

[self fetchedResultsController] performFetch:&error]

in the console i also get this message:

unable to load symbol file: unable to load symbol file: warning: Unable to read symbols for /Developer/Platforms/iPhoneOS.platform/DeviceSupport/4.3.3 (8J2)/Symbols/Developer/usr/lib/libXcodeDebuggerSupport.dylib (file not found).

As i haven't found anything that could help me, i guess it's either something really weird, or i just messed up something pretty standard, that i can't find because of my limited objective c background...

Anyway, i would be very glad if someone could give a hint, so i can continue without having to rewrite my entire application model layer to something dirty (like fetching all entries and holding them in an array and process filter functions...stuff like that ;) )

edit:

here is the model graph. from this auto-generated the model files.

Link to Image

generated HappyHour class:

@interface HappyHour :  NSManagedObject  
{
}

@property (nonatomic, retain) NSDate * endTime;
@property (nonatomic, retain) NSDate * startTime;

@end

retendo retendo · Accepted Answer · 2011-06-28T11:38:54

i figured it out. Hopefully this will help someone, who is as blind, tired or whatever as myself. ;)

These bold marked passages clearly don't match:

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Unable to generate SQL for predicate (0 != SUBQUERY(details.hh_montag, $hh, $hh.startTime < CAST(316482000.000000, "NSDate") AND $hh.endTime > CAST(316482000.000000, "NSDate")).@count) (problem on RHS)'

and

@class Location;

@interface LocationDetails : NSManagedObject { }

@property (nonatomic, retain) NSString * phone;

...

@property (nonatomic, retain) NSSet * hh_monday;

...

@end

The final solution was:

NSTimeInterval secondsPerDay = 7 * 60 * 60;
NSDateFormatter *f = [[NSDateFormatter alloc] init];
[f setDateFormat:@"EEEE"];

SOLUTION >> [f setLocale: [[[NSLocale alloc] initWithLocaleIdentifier:@"en_UK"] autorelease]];

NSString *weekdayString = [NSString stringWithFormat:@"hh_%@", [[f stringFromDate:[NSDate dateWithTimeIntervalSinceNow:-secondsPerDay]] lowercaseString]];

Golden Rule:

Always keep in mind, that a device will work differently in a different location/language.

So, maybe avoid producing key selectors(?) from location/language-dependent classes like NSDate(Formatter).
Or make sure, that these classes return the same values for every case. (Hopefully something I have taken care of with this solution...correct me if I got that wrong.)

Core Data NSFetchedResultsController: Error when debugging on device (Unable to generate SQL for predicate)

1 Answers