How to add attributes to an existing Core Data entity (object) programmatically?

I would like to add attributes programmatically to an entity during runtime of my app.

Is this something you would recommend doing or can this lead to issues?

How would I need to combine NSAttributeDescription and NSEntityDescription? I am familiar with creating models using Xcode, but did not do it using NSEntityDescription yet.

It's theoretically possible, but doesn't appear very practical.

You can modify the NSManagedObjectModel programmatically, as well as NSEntityDescription. Note that -setEntities: (NSManagedObjectModel) and -setProperties: (NSEntityDescription) both trigger exceptions if you modify a model that has been instantiated. So you can't modify your existing model's structure. You'd have to create a new one and copy all of your data from the old Core Data stack to the new one based on your new model..

Using NSMutableDictionary is a much saner approach.