Re: Recommended way to save NSPredicates in Core Data store?
Re: Recommended way to save NSPredicates in Core Data store?
- Subject: Re: Recommended way to save NSPredicates in Core Data store?
- From: Ken Thomases <email@hidden>
- Date: Wed, 15 Aug 2018 19:29:05 -0500
On Aug 15, 2018, at 6:15 PM, Demitri Muna <email@hidden> wrote:
>
> I'm building an interface that contains an NSPredicateEditor (think iTunes
> smart playlists), and I want to save the predicate in a Core Data store. What
> is the recommended way to do this? Serialize the NSPredicate object and save
> it as a blob? Break apart the predicate into one or more NSExpressions (left
> hand value, operator, right hand value) and reconstruct the predicate? I can
> think of several possibilities, but am wondering what is the path of least
> resistance (and, I suppose, most binding-friendly!).
Serializing the predicate (using NSKeyedArchiver) seems obviously the right way
to go. Any other approach is just reinventing serializing it in a worse way.
You can create a custom value transformer (subclass of NSValueTransformer) to
automatically archive and unarchive. Use that on your binding.
Regards,
Ken
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