iphone - How to setup a predicate for this query -

I have a 3 object hierarchy in which the 'division' is original, in which many 'group' items and each ' Group 'has many employees.

division [1] ------ [*] group

group [1] ------ [*] employee

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I would like to know how to create an NSPredicate for the search of all employees of all groups of a specific division, the creation has been sorted by date / time and classified using their 'group' To know the 'Employee' object and specific division ID as the requested entity.

But I'm having trouble translating it into CoreData, so any suggestion would be helpful.

i was to create a SQL query, this would be something like this:

Select from employee * where - in exampleEdId (select * from group * g.divisionId =: DivisionId )

I tried to do this but did not work:

  // Create a fetch request for the institution. NSFetchRequest * fetchRequest = [[NSFetchRequest alloc] init]; // Configure the unit of the request and its definition NSEntityDescription * entity = [NSEntityDescription EntityForName: @ Managed object contexts in "employee": context]; [FetchRequest Set Entity: Entity]; // Create undoubtedly NSPredicate * predicate = [NSPredicate predicateWithFormat: @ "SELF.groups IN% @", [NSArray arrayWithArray: [[Employee groups] allObjects]]]; [FetchRequest set candidate: count]; // Edit the sort key as appropriate NSSortDescriptor * createDateSortDcptor = [[NSSortDescriptor alloc] initWithKey: @ "createDateTime" ascending: yes]; NSArray * sortDescriptors = [[NSArray alloc] initWithObjects: createDateSortDcptor, zero]; [Set FetchRequestSercript: Sort Descriptor];  

My object hierarchy is this:

  @ Interface Division: NSManage Object {} @ property (nontomic, write) NSDT * createDateTime; @property (nonatomic, retain) NSSet * groups; @end @text group: nsmainage object {} @property (nontomic, rETAIN) NSDT * create time; @property (nonatomic, intact) division * division; @property (nonatomic, retain) NSSet * employee; @ And @ interface staff: NSManagedObject {} @property (nonatomic, retain) NSDate * createDateTime; @property (nonatomic, retain) NSSet * groups; @end