Google AppEngine Data Store explained

Since the Data Store behind Google’s AppEngine is not a relational database I have been wondering all along how to manage one-to-many and many-to-many relationships. This links to the Java documentation:

http://code.google.com/appengine/docs/java/datastore/relationships.html

And here are some well explained examples in Python:

http://arbingersys.blogspot.com/2008/04/google-app-engine-one-to-many-join_26.html

http://arbingersys.blogspot.com/2008/04/google-app-engine-many-to-many-join_28.html

http://arbingersys.blogspot.com/2008/04/google-app-engine-better-many-to-many_30.html