Hi,

I am using hibernate client-side for persistence, and it is working great. This is difficult for concurrency checks of course.
How can I check if an object that is in the local hibernate cache is still the latest version in the database. Is it even possible to check if an object that has been changed locally (but not saved yet) has not been changed in the database in the meantime?

Regards,
Leen Toelen

Hi,

you can try the refresh method in Session class.
For checking if your instance is already dirty I think
there was another thread some weeks ago.
Try searching for isDirty or something like that.

In Hibernate there is a technique integrated called "Managed Versioning".
For this purpose you need to add to your mapping hbm.xml-files following line beneath the </id> tag:

Don't forget a column in your regarding table with that name.
You also need a deklaration in your mapping class

..and of course a getter and setter method.


Everytime you update an entity, hibernate adds to the update statement someting as WHERE hbversion=2 (suggesting that 2 was the version when you read the entity).
After updating hibernate checks the returned 'effected-rows' value and if it's zero, then an exception will be thrown: StaleObjectStateException. With this Exception you get the information, that a different transaction already updates the entity.

I hope you get what I meant and I told it exactly ;)

best regards

I call hibernate lock with nowait option - if lock doesn't success then another user change object - this lock objects for another user , too

This work for databases with lock nowait option (oracle , postgresql ?)

Here's another thread on this topic. Our strategy is to not actually change the versioned objects until the user clicks save. Then we lock the objects for upgrade, and check the versions. If they've changed, we flush and commit (releasing all locks), and ask the user what to do, then repeat.

Cheers!
Rob