I just want to make sure my understanding is right. Since GAE datastore use optimistic locking for transaction control, it's very easy to detect concurrent modification thus it can decide whether a transaction commit will succeed or fail.
But when creating new entities, what is used to decide a transaction commit will succeed or fail. If for example I just want one copy of an entity with the same properties values. I've read a lot of related posts and articles and I get the understanding that the Key instance generated by the datastore is used to decide. If I multiple concurrent transaction use the same entity kind and key name/id, the generated Key instance will be the same and only one transaction commit will succeed. Is my understanding correct and is using key name/id the only way to achieve this? Thanks a lot for any response! -- 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.
