Core Data: Generating an interface for an entity

The new Core Data framework and Xcode 2 modeling tools in Tiger are an extremely powerful way to develop great end-user applications quickly. You can even easily generate a human interface for your application that will let you work with its data model with little to no code.

To generate an interface, create an empty window in Interface Builder and make sure you’ll be able to see it with Xcode in front. Switch to your model in Xcode. Then just option-drag the entity you want an interface for into your window. Interface Builder will ask you whether you want an interface for one or many instances of that entity, and then generate a basic form-style human interface for all of the attributes and to-one relationships in that entity.

This generated interface isn’t a special monolithic “NSCoreDataControl” or anything of the sort. it’s composed of standard Cocoa controls that wired to standard Cocoa controllers via bindings. If your nib file’s owner is set to be an instance of NSPersistentDocument or a subclass, Interface Builder will even bind the controllers’ managed object contexts to the document’s.

If you just want to create controllers rather than full interfaces, or if you want to update the controllers in your nib file with the latest definition of your entity, drag the entity from your model straight to your nib’s document window. (That’s the one with the tabs for classes and instances etc.)

Note that none of this, none of this requires generating or writing code. You can create a new Core Data Document-based Application from the project template, create a data model for it in Xcode, create an interface for it in Interface Builder, and then build and run it. You can create, save, load, and manipulate documents and even undo and redo changes and avoid saving invalid data with no code.