I currently have a cardType attribute on my entity, which in the old model could be "Math", "Image" or "Text". In the new model, I'll be using just "Math" and "Text" and also have a hasImage attribute, which I want to set to true if the old cardType was Image (which I want to change to "Text").
Lastly, I have a set of another entity, "card", of which a set can be associated with a deck, and in each of those, I'll also have hasImage which I want to set to true if the deck was of "Image" type before.
Is this all possible using the Value Expression in the Mapping Model I've created between the two versions, or will I have to do something else?
I can't find any document telling me exactly what is possible in the Value Expression (Apple's doc - http://developer.apple.com/library/mac/#documentation/cocoa/conceptual/CoreDataVersioning/Articles/vmMappingOverview.html%23//apple_ref/doc/uid/TP40004735-SW3 - only has a very simple transformation). If I have to do something else, what would that be? This seems simple enough that an expression should be able to do it.