Can I use the saveOrUpdate method when my id generator is "assigned"? I would have to set the id property of the entity I want to persist, so how would Hibernate know to save or update based on the unsaved-value? Thanks.

I guess it can only work if you have a version field.

you can also use an Interceptor ... (then you can do what ever you need to help hibernate to find out if an insert or update is required) ...

In the mapping, can you not set the 'unsaved-value' property of the id to 'undefined'? This should force hibernate to check the database to see if the object has been persisted previously or not.

Thanks all. I'll try setting unsaved-value to undefined and see what happens. I'll keep you posted.

In cases like this,
use <version> or <timestamp> properties in the mapping file. It works, we have been working with the same thing.