Have you tried to use Core Data in RubyMotion, only to get lost in the quagmire of simplistic or confusing examples, DSL's and gems?
Well, Core Data in Motion has got you covered. I went out and shaved that herd of yaks so you don't have to. And now I'll be serving it up in nice uniformly stuffed pillow-shaped pieces, I mean chapters.
Core Data in Motion is an ebook, tackling each of these problems head on, one chapter at a time, with a brief historical review of "the XCode/Objective-C way", and then providing a detailed, code-oriented solution using RubyMotion and the iOS SDK.
After we've achieved that base-level understanding of how Core Data actually works, we'll review the available RubyMotion gems which may provide even simpler solutions, but you'll now be able to understand exactly which problems those gems solve for you, which problems they do not, and be confident that you've chosen the best option to solve your specific problems.
Core Data is hairy because it solves real problems - http://sealedabstract.com/code/you-should-use-core-data/.
If you are using RubyMotion to solve real problems, with a real data model, and complex data relationships, you need Core Data, and you need this book.