|
Hi, I'm a newbie myself, but I'll try to answer anyway from my understanding of the docs, just to see where I get corrected.
1. If you are only interested in the changes to a specific record at a specific point in the code, and you haven't made any changes to that object in your own application, AFAIR you can update the contents of the in-memory object from the database by calling session.refresh( object ) (NOT session.update(...) - that does something else entirely...).
2. If the other application is the one writing to the records, and you are only reading them (not changing them), it depends on how up-to-date your application's knowledge of the records has to be. Hibernate loads the record when it's first accessed in a Session (or when its contents are accessed in the case of a lazily loaded object), and then keeps the object state cached for the duration of that session (i.e. the session is the mandatory first-level-cache). If you need the object to be more up-to-date, you need to call session.refresh... see above. BUT this answer is only correct as long as you don't have any second-level-caches configured for that object ("<cache-use=...") - in this case, the object will be cached longer than the single session.
3. If both the other application and your application are updateing these records, and it's possible both will be trying to update the same record (row) more or less at the same time, and it's not acceptable for any of these changes to get overwritten - then things get more complicated, and you'll have to implement some kind of optimistic locking / versioning scheme (probably in the other application, too). There is some support in Hibernate for that (see chapter 10 in the reference documentation), but I don't have any experience with that, so I can't give you more concrete tips here.
Hope this helps anyway,
=) Phouk
|
Login
FAQ
Search