I have a reasonably complex core data data model which makes use of entity inheritance. In an attempt to make use of the new Leopard data migration tools, I created a new version, made a few minor desired changes (added a few entities and created the relationships to them- no changes to existing entities except new relationships to new entities).
My first attempt to create the mapping model failed because the automatically created mapping model would not compile. I eventually tracked it down to the fact that mappings were not being created for entities from which some other entity derived (that is, no base entity had a mapping model created for it). As a result, any relationship to a base entity did not have a valid value expression because no appropriate mapping was found. I was able to fix the above by creating the missing mappings, which seemed to automatically fix the relationship mappings. Once I also got the mapping and models into my application rather than its framework, Core Data was successfully finding my source data model and attempting the migration. However, the migration would fail with "Model already contains an entity named VCText." The VCText entity is one that derives from another entity, and it is my guess that this is a result of a child entity being transformed twice- once because of the parent entity mapping that I had to create, and then again because of the child entity mapping. To sum up: Relationships to entities from which another entity inherits are not automatically set up properly. There only appear to be two solutions: a) Create the missing base entity mappings. This appears to cause transformation failures, I assume because of double transformations b) Fix the relationships by, rather than trying to use a base entity mapping, simply picking one of the child entities (even though the relationship is supposed to be to the base). This also seems likely to fail to transform all relationships properly. Anyone have any experience with this, or know how to handle this situation? I suppose I could write a whole bunch of custom code to handle it, but it seems as if the migration system should handle the inheritance. -- - David T. Wilson Princeton Satellite Systems [EMAIL PROTECTED] _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) 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]
