David Chandler's Journal of Java Web and Mobile Development

  • David M. Chandler

    Web app developer since 1994 and Google Cloud Platform Instructor now residing in Colorado. Besides tech, I enjoy landscape photography and share my work at ColoradoPhoto.gallery.

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How to do joins in AppEngine

Posted by David Chandler on January 25, 2010

So the AppEngine DataStore DOES do joins, after all… using the mysterious list properties. This is highly recommended viewing for anyone building a large social application or otherwise looking for a simple alternative to a SQL inner join. You cannot organize your data model quite the same as you would in a relational database, but you can easily simulate querying an intersection table.

Building Scalable, Complex Apps on AppEngine

3 Responses to “How to do joins in AppEngine”

  1. Rusty Wright said

    I think that, for me at least, part of the problem with understanding the GAE Big Table data store is that Google pushes using JDO or JPA on the java side for interfacing with the data store. Both of those are heavily oriented to SQL databases, even though JDO can work with lots of non SQL things. I’m thinking that what’s needed is some new ORM that’s designed from the start for non SQL databases, or designed just Big Table. For GAE, at the moment, there are Twig, SimpleDS, and Objectify, and probably others.

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