"bstansberry(a)jboss.com" wrote : | I was trying to think how this could break things; e.g. app removes some data and then tries to recreate it. Say an admin creates a "user" account entity; realizes he's mucked it up, deletes it and starts over with the same id. He could get version conflicts when he starts over. | Well, not necessarily. Version != identity. He would be allowed to add it again, the version would increment without a problem. Where it *does* step in is if 2 admins attempt to create the same id, but that is a valid conflict anyway. "bstansberry(a)jboss.com" wrote : | 3) If explicit data versioning is used, it could be a problem. But perhaps that can be handled in the Hibernate/JBC integration, which separately handles cache insertions of newly created entities. Again, it shouldn't be a problem if used correctly. Explicit versioning should only be used if there is an external "true representation of state" (such as a database) which also maintains versioning for that state. Explicit versioning is only meant to be a way to expose the versioning maintained by the database. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4097214#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...