I have a class which as its properties has a number of NSSet values. The content of these sets is not stored in Core Data, but comes from another source. They are basically ID strings which are unique. No point in filling up Core Data with them as separate entities.
However, as far as I can see it's not possible to store an NSSet as an attribute of an NSManagedObject. I guess I would need to serialise it into binary data by hand, whenever the object gets stored, and deserialise it when it gets retrieved from the persistent store? The same would also apply to storing other collection classes.
Has anybody else ever come across this issue and is able to give some advice?
You can set the attribute type to 'transformable' and then directly store the set into the attribute. Be sure that all of the contents of the set conform to < NSCoding >.