NSFetchedResultsController Creating Sections - iphone

Question

When using the NSFetchedResultsController to create section headers for the UITableViewController the fetchedResultsController.sections has an object for each item not each section.
//Set up the request
NSManagedObjectContext *context = self.managedObjectContext;
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
[fetchRequest setEntity:[NSEntityDescription entityForName:#"Person"
inManagedObjectContext:context]];
[fetchRequest setFetchBatchSize:20];
NSSortDescriptor *sortDescriptor = nil;
sortDescriptor = [[NSSortDescriptor alloc] initWithKey:#"firstName"
ascending:YES];
NSArray *sortDescriptors = nil;
sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];
[sortDescriptor release]; sortDescriptor = nil;
[fetchRequest setSortDescriptors:sortDescriptors];
[sortDescriptors release]; sortDescriptors = nil;
//setup fetch results controller
NSFetchedResultsController *controller = nil;
controller = [[NSFetchedResultsController alloc]
initWithFetchRequest:fetchRequest
managedObjectContext:context
sectionNameKeyPath:#"firstName"
cacheName:#"PersonCache"];
__fetchedResultsController = controller;
[fetchRequest release]; fetchRequest = nil;
//IMPORTANT: Delete cache before changing predicate
[NSFetchedResultsController deleteCacheWithName:nil];
NSError *error = nil;
if (![controller performFetch:&error])
{
NSLog(#"Unresolved error %#, %#", error, [error userInfo]);
abort();
} else if ([[controller fetchedObjects] count] == 0){
[self retrievePeoples];
}
NSLog(#"result count: %i", [[controller fetchedObjects] count]);
NSLog(#"section count: %i", [[controller sections] count]);
NSLog(#"sectionIndexTitles count: %i", [[controller sectionIndexTitles] count]);
This returns:
result count: 18
section count: 18
sectionIndexTitles count: 13
Shouldn't the section count and the sectionIndexTitles count match? When the numberOfSectionsInTableView: and tableView:numberOfRowsInSection: methods are called I should just be able to look to the fetchedResultsController.section for a count without any additional sorting.
How do I setup the NSFetchResultsController properly to have each object in the sections array be for per section and not for all objects?

Answer 1

This was answered by Phillip Mills on another forum. The problem was I was using the entire firstName to create sections (not just the first letter). The fix is to update the entity to create the a section title whenever updated or changed. Apple's DateSectionTitles has a sample of what to do.