On 2010 Sep 09, at 04:14, Amy Gibbs wrote: > I didn't really want to save the values as attributes, as I'd like the values > to reflect changes to the product prices. I only need to display these in a > label onscreen. > > Is this what transient attributes are for?
Yes, but before you use transient attributes, be sure to study all their limitations given in the Core Data Programming Guide. I am not a fan of transient attributes, as you can read here: http://www.cocoabuilder.com/archive/cocoa/237109-only-one-reason-to-ever-use-transient-properties-in-core-data.html?q=only+reason+transient+attributes#237109 http://www.cocoabuilder.com/archive/cocoa/234791-core-data-fetches-transient-properties-nspredicateeditor-sadness.html?q=only+reason+transient+attributes#234899 Unless you have a user base of millions, or are a fantastic programmer, it's hard to beat today's hard drive prices of less than a dollar per gigabyte. So the smartest solution is often to just leave the "unnecessary" attributes in the persistent store, and start on your next project. Another alternative is to add a regular instance variable to your managed object. Regular ivars still work. Or, in this case, it appears that calculating them as needed and implementing +keyPathsForValuesAffectingXxxxx to make them KVObserveable would work and get you home on time. _______________________________________________ Cocoa-dev mailing list ([email protected]) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [email protected]
