Most recent search results join in Core Data

Answer 1

You should be able to have a sort descriptor that follows relationships:

NSFetchRequest *request = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Entry" 
                                          inManagedObjectContext:context];
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] 
                                    initWithKey:@"history.createdAt"
                                      ascending:NO];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:&sortDescriptor
                                                      count:1];
[request setEntity:entity];
[request setSortDescriptors:sortDescriptors];
[request setFetchLimit:1];
fetchedResultsController = [[NSFetchedResultsController alloc]
                            initWithFetchRequest:request
                            managedObjectContext:context 
                              sectionNameKeyPath:nil 
                                       cacheName:@"Root"];