As Jeff and others already posted, JPA on AppEngine just don't work as you expect (from the JPA point of view), and others just work as you don't. I'm the team leader of a running GAE/J application and we are, like Jeff says, * screaming* because of my decision to use JPA. We were about to consider using JDO, due to it's non-RDBMS options, but looks like the best choice is another tool like Objectify or Twig-persist.
We are now trying out those tools to do come poof-of-concept in our codebase. A good choice is to encapsulate your datastore using a DAO or Repository pattern (or even both!), since they may help you to change your mind in the future. We did it and now we can try out some other tools on top of the Low Level API. In regards of the Objectify library, +1 for the helpers on schema migration. This is very (very!) hard to acomplish on a real-world web app when using JDO/JPA, and is a very usefull feature. In any case, now the RemoteApi is also available in Java (as per 1.4.4) and this is very useful to do some data export, local fixture loading and others. So, it is nice to at least know how the datastore works, it may help you in the future. -- You received this message because you are subscribed to the Google Groups "Google App Engine for Java" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine-java?hl=en.
