Re: Core Data: right way to gather all elements of a to-many relationship?
Re: Core Data: right way to gather all elements of a to-many relationship?
- Subject: Re: Core Data: right way to gather all elements of a to-many relationship?
- From: "I. Savant" <email@hidden>
- Date: Wed, 11 Feb 2009 15:16:27 -0500
On Wed, Feb 11, 2009 at 2:48 PM, Luke Evans <email@hidden> wrote:
> The parent MO is defined with an 'elements' property (nominally an NSSet).
How? What does this declaration look like in your classes? I assume
you have at least one custom subclass of NSManagedObject specified
(for your "Element" entity), based on the code example you gave, but
it's important to let us know *how* this is declared.
> So for simply reading the set and converting it to an array, I had imagined
> the following would be OK:
>
> NSArray *elements = [parent.elements allObjects];
>
> Now, this turns out to be bad, as on occasion (and I think, when there are
> no elements), I get the error:
> *** -[NSCFArray allObjects]: unrecognized selector sent to instance
> <whatever>
I'd be just as surprised as you - I've never run into this problem
personally and would've expected it to produce a set, not an array.
Then again, I'm still begrudgingly sticking to Obj-C v1 on all but my
newest project, so it may have something (or a lot, or everything) to
do with Obj-C 2's dot syntax or synthesized properties, and not Core
Data.
--
I.S.
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