NSPredicate Core Data to-many - ios

Question

This is the Core Data model. Image
DiaCD <--->> HoraCD <<---> ActividadCD
In the entity "Activity" is a category called attribute to filter the activities. My question is: How could I make a query to give me back the days with activities where the category is "X"?
Try one:
NSEntityDescription *entityDescriptionDia = [NSEntityDescription entityForName:#"DiaCD" inManagedObjectContext:managedObjectContext];
NSFetchRequest *requestDia = [[NSFetchRequest alloc] init];
NSPredicate *predicateDia = [NSPredicate predicateWithFormat:#"ANY relDiaHora.relHoraActividad.categoria == %#", categoria];
[requestDia setEntity:entityDescriptionDia];
[requestDia setPredicate:predicateDia];
NSError *errorDia;
NSArray *arrayDia = [managedObjectContext executeFetchRequest:requestDia error:&errorDia];
if ([arrayDia count] > 0) {
for (DiaCD *dia in arrayDia) {
NSSet *setHora = dia.relDiaHora;
HoraCD *horaQuery = [setHora anyObject];
ActividadCD *actividadQuery = horaQuery.relHoraActividad;
NSLog(#"Act --> %# y la categoria --> %# y la categoria --> %#", actividadQuery.titulo, actividadQuery.categoria, categoria);
}
}
If I do this query does not return good data that does not respect the category, I'm guessing, do not know why :S.
Try 2:
NSPredicate *predicateDia = [NSPredicate predicateWithFormat:#"relDiaHora.relHoraActividad.categoria == %#", categoria];
If I do the same query but only removing the "ANY" fails. Error: "reason: 'to-many key not allowed here'"

Answer 1

Your predicate
[NSPredicate predicateWithFormat:#"ANY relDiaHora.relHoraActividad.categoria == %#", categoria];
returns all days that have any hour with the given activity category. Your problem seems
to be that
NSSet *setHora = dia.relDiaHora;
returns all hours of the fetched day, not only the hours with the given activity category.
Therefore
HoraCD *horaQuery = [setHora anyObject];
is any hour of the fetched day, and need not have the given activity.
If you need the days and matching hours, you should execute a fetch request on the hours
instead:
NSEntityDescription *entityDescriptionHour = [NSEntityDescription entityForName:#"HourCD" inManagedObjectContext:managedObjectContext];
NSFetchRequest *requestHour = [[NSFetchRequest alloc] init];
NSPredicate *predicateHour = [NSPredicate predicateWithFormat:#"relHoraActividad.categoria == %#", categoria];
[requestHour setEntity:entityDescriptionHour];
[requestHour setPredicate:predicateHour];
NSError *errorHour;
NSArray *arrayHours = [managedObjectContext executeFetchRequest:requestHour error:&errorHour];
if ([arrayHours count] > 0) {
for (HourCD *hour in arrayHours) {
DiaCD *dia = hour.relHoraDia;
ActividadCD *actividad = hour.relHoraActividad;
// ...
}
}

Answer 2

OK, the first bit was wrong. However, still follow this note about naming.
A QUICK NOTE
You should not be calling your attributes "relItem1Item2". This is something that comes from relational databases. CoreData is not a relational database.
You should name them descriptively as to what they point to.
i.e.
relHoraActividad should be called actividad. As it is pointing to the actividad entity and it is a "to-one" relationship.
Also...
relActividadHora should be called horaCDs. It is pointing to the horaCD entity and it is a "to-many" relationship.

Answer 3

I think your setup is absurd. Why have complicated relationships to days and hours when you can simply use NSDate attributes?
From your image I see that you store other things in these entities that do not seem to have anything to do with hours or days.
To filter by day or time, you typically use a pattern like this
[NSPredicate predicateWithFormat:#"time > %# && time < %#", min, max];