Ответ 1
Используйте это:
NSEntityDescription *entityDescription = [NSEntityDescription entityForName:@"Friends" inManagedObjectContext:context];
NSFetchRequest *request = [[[NSFetchRequest alloc] init] autorelease];
[request setEntity:entityDescription];
[request setPredicate:[NSPredicate predicateWithFormat:@"firstName == 'George'"]];
NSError *error = nil;
NSArray *array = [context executeFetchRequest:request error:&error];