Difference in data when using core data relationships - iphone

Question

I'm using core data to fetch values from an sql lite database for my iphone app. I'm pretty new to the syntax so I might be missing a few key infos.
My fetch request looks like this:
NSEntityDescription *difficultyDescription = [NSEntityDescription entityForName:#"Difficulty" inManagedObjectContext:managedObjectContext];
NSFetchRequest *fetchRequest = [[[NSFetchRequest alloc] init] autorelease];
[fetchRequest setEntity:difficultyDescription];
NSArray *diffResults = [managedObjectContext executeFetchRequest:fetchRequest error:&error];
After that, I'm looping through the results by using this snippet:
systems = [[NSMutableArray alloc] init];
values = [[NSMutableArray alloc] init];
for (NSManagedObject *diff in diffResults) {
[systems addObject:diff];
[values addObject:[diff valueForKey:#"difficultyValues"]];
}
What I don't get about this is, that when I log systems by using
NSLog(#"%#", [[systems objectAtIndex:0] valueForKey:#"name"]);
I get the result in plain text. For example "some value".
When logging the results in the "values" array however I get this result:
{(
"some value"
)}
I'm using the same logging call:
NSLog(#"%#", [[values objectAtIndex:0] valueForKey:#"value"]);
The entities difficulty and difficultyValues have a one to many relationship.
How can I display the value in the array "values" like the one in "systems"? I need it later on for a label.

Answer 1

This seems to be a fundamental misunderstanding. difficultyValues is a relationship, while name is an NSString attribute. That's why it appears differently in NSLog(), which works by sending objects a -description message.
The value for difficultyValues will be an NSSet which contains multiple managed objects for the entity difficulty.
Here's what you should do:
NSLog(#"%#", [[systems objectAtIndex:0] valueForKey:#"name"]); // NSString*
// let's loop through all the difficulties of this item
for (NSManagedObject* aDifficulty in [[[systems objectAtIndex:0] valueForKey:#"difficultyValues"] allObjects]) {
NSLog(#"%#", [aDifficulty valueForKey:#"name"]);
}
This, of course, assuming your difficulty entity has a name attribute.