Where to find the documentation of the SUBQUERY feature of NSPredicate for Core Data?

Question

Where to find the documentation of the SUBQUERY feature of NSPredicate for Core Data?

Answer 1

Good question.

The only thing I found was a reference to NSSubqueryExpressionType in the NSExpression documentation, which is what is used when you specify SUBQUERY in your predicate.

I also found a couple of examples in the expressionForSubquery:usingIteratorVariable:predicate: method of the same document.

This seems like it should be in the Predicate Programming Guide, but the only mention of it there is in the reserved words section.

I found some mentions of it in the huge Frameworks Foundation Reference, but these are mostly duplicates of the previous stuff I linked to.

Here's the Google search query I tried using, which only returned 14 results.

Hopefully someone else is more successful.