Question

Okay, so I already tried the examples on apple’s SDK developer pages and it didn’t work. I tried the examples from previous questions on stackoverflow like :

NSEntityDescription  entitydesc = [NSEntityDescription entityForName:@"Model" inManagedObjectContext:context];
NSFetchRequest request = [[NSFetchRequest alloc]init];
[request setEntity:entitydesc];

//tried this style of predicate

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"accessible == %@", [NSNumber numberWithBool:YES]];

//and this one

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"accessible == YES"];
[request setPredicate: predicate];

NSError *error;
NSArray *matchingData = [context executeFetchRequest: request error: &error];

both of which didn’t work. In debugger the matchingData shows 0 objects when it should have many.

All my other fetchrequests have worked perfectly fine. This is the only one giving me problems.

The attribute is listed as type Boolean in the .xcdatamodel

The attribute is listed as this under the entity’s header file:

@property (nonatomic, retain) NSNumber * accessible;

The data was entered into the core data database as follows:

NSNumber *accessibleFieldValue  = [NSNumber numberWithBool:YES];
[newModel setValue: accessibleFieldValue forKey:@"accessible"];

I’ve checked and there are no nil values entered in the sqlite database.

What should I do?

Answer 1

I ended up going to the database in sqlite database browser and changing the type for the field value to Numeric. For some reason core data entered the data as an incompatible data type…..don’t really know why, but I have a feeling this might be an Xcode bug. As I said, it works now after I changed the field type. I don’t think I will be using boolean values in core data any time soon…..at least not until I understand why this was a problem.