[alius]

Hi,

GAE engine's transactions are NOT the same as normal RDBMS.
I've intentionally pointed you to check specifics.

You can not fetch/update/delete entities which do not belong to the same group in a single GAE transaction. Check this:
http://code.google.com/appengine/docs/java/datastore/transactions.html#What_Can_Be_Done_In_a_Transaction

EMFProviderNoTransactions was created for GAE - it does not start transactions at all (actually works faster). Using it you have to ensure referential integrity yourself.

BTW: GAE data store has very limited filtering operators therefore implementing AdvancedCriteria is almost impossible.

Alius

[atomatom]

Thanks Alius. It's working great now. I'm not executing any more DSRequests on the server, but my optionDataSource definitions don't cause exceptions anymore.

It would be a good idea to update the SmartGWT GAE-DS sample to use the correct settings, as outlined in this thread.

And yeah, I can see the pain in trying to adapt AdvancedCriteria for GAE. Anyway, my life got much better when I switched over to DMI methods. Simpler, easier to debug/test, and more control on queries.