Bumble is a very small wrapper around DataStore, that allow you to create data models backed by Google’s DataStore. It was developed to back YARBL, so it really only supports the things needed for that application.

This is what the data model for YARBL looks like. This should give you a feeling for how you define models with Bumble. One thing to remember is that the DataStore actually allows any properties/attributes on entitites, so it fits a language like Ruby very well.

class Person
  include Bumble

  ds :given_name, :sur_name, :email
  has_many :blogs, Blog, :owner_id
end

class Blog
  include Bumble

  ds :name, :owner_id, :created_at
  belongs_to :owner, Person
  has_many :posts, :Post, :blog_id, :iorder => :created_at
end

class Post
  include Bumble

  ds :title, :content, :created_at, :blog_id
  belongs_to :blog, Blog
end

To actually use the model for something, you can do things like these:

Blog.all

Post.all({}, :limit => 15, :iorder => :created_at)

blog = Blog.get(params[:id])
posts = blog.posts

Blog.create :name => name, :owner => @person, :created_at => Time.now

Post.all.each do |p|
  p.delete!
end

Here are most of the supported methods. The implementation is incredibly small and you really can’t go wrong with it. Of course, it is not tuned at all, so it does lots of fetches it could avoid. I’m happily accepting patches! The code can be found at github.com/olabini/bumble.

Taken from “Jruby on Rails on Google App Engine, APRIL 8TH, 2009” at olabini.com/blog/2009/04/jruby-on-rails-on-google-app-engine