CoreDataBooks Example Saving Conditions

I have based a large portion of CoreData functionality n my app on the CoreDataBooks example by Apple. There is a specific attribute, for me the 'name', that must be filled in before saving is possible.

How can I alter the code to only allow saving under certain circumstances? Such as only saveable when that name field is not empty?

Yes, there is an "optional" option for your entity attribute. First select the attribute then in the side bar un-check optional, see image below. Also there is a validation option where you can define: min. and max. lengths, and default values.