Should have typed migraine with abstract entities…
I have a model based on the SortedTree example posted here http://jonathandann.wordpress.com/2008/05/13/nstreecontroller-and-core-data-sorted/
This model uses an abstract entity to represent a TreeNode and two entities that inherit from TreeNode (Group and Leaf). All has been fine until now when I am trying to implement data migration to allow the application to upgrade data files for new additions to the model.
I am trying to use the AutoMigration but generating a mapping model fails to include all the abstract entities attributes and relationships to the Group and Leaf entities and then fails because of multiple validation errors when trying to upgrade.
Any ideas on whether this is a bug or expected behaviour and if so then how does one migrate this data model ? Is there any plan to fix this ?
Any references to simple examples showing how to create a custom migration policy - there are no actual changes to these entities in the new model I just need to copy the data across.