CoreData: fetchRequest on a subTable - ios

Question

How can I add a Subcategorie to a Categorie?
And how can I get the specific Subcategorie's of a Categorie?
I need something like
get Subcategorie.denumire where Categorie.denumire == "somename"
and
add mySubcategorie to Categorie.denumire where Categorie.denumire == "somename"
How can I do this? How can I get the name of a subtable's parent table and the names of the subtables of a table?

Answer 1

When you generate NSManagedObject Entities, Goal class will have an NSSet called toMinorGoal (assuming, your toMinorGoal is unordered relationship). Also, XCode will generate 4 accessory methods to add/remove MinorGoal objects to/from relationship.
If you need to fetch MinorGoals object, you would just need to get Goal object and then access its toMinorGoals NSSet that will contain all of its MinorGoal objects. Alternatively, you can just fetch MinorGoal objects, but these will return every single one of them (if you don't specify how many you want).
This is an approximate example of generated accessors XCode will provide you with:
- (void)addtoMinorGoaObject:(MinorGoal *)value;
- (void)removetoMinorGoalObject:(MinorGoal *)value;
- (void)addtoMinorGoal:(NSSet *)value;
- (void)removetoMinorGoal:(NSSet *)value;
Hope it helped you.

Answer 2

After a few day's of trying different solutions I finally figured this out thanks to this tutorial on CoreData :
http://www.raywenderlich.com/934/core-data-tutorial-for-ios-getting-started
I fetched all the subtables Subcategorie of the table Categorie like this:
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"Subcategorie"
inManagedObjectContext:self.managedObjectContext];
NSPredicate * predicate = [NSPredicate predicateWithFormat:#"categorii.denumire == %#",self.title];
[fetchRequest setPredicate:predicate];
[fetchRequest setEntity:entity];
NSError *error;
self.listaElementeBD = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];
self.title is the denumire of the Categorie, hope this helps.