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Re: Non-standard attributes - avoid warning from data model compiler?

On May 31, 2005, at 5:41 PM, Dan Messing wrote:
Or remove the transient attribute, which I believe will only break undo/redo, which you would then have to implement yourself for the custom attribute. I'm no authority on the subject though, so someone please correct me if I'm wrong here.

A transient attribute will not break undo/redo. In fact, the main reason to use a transient attribute is to have an attribute that isn't persistent but is nonetheless managed.

One use for a transient attribute is to represent a value type (class) that Core Data doesn't natively support — such as NSColor or one of your own value classes — and use a persistent attribute as "backing store" for it. Another use is for a derived attribute that you want to appear in your model, because you have code that walks your model, or because you want to drop your entity on IB to generate an interface or a controller. In the former case you'd get undo/redo support for your attribute, in the latter it would be effectively read-only.

  -- Chris

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 >Re: Non-standard attributes - avoid warning from data model compiler? (From: Dan Messing <email@hidden>)



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