This is a technical question about cascading updates and the way they affect version numbers on child/parent objects.

I've notice that with my current setup, which makes use of:
- integer version numbers
- optimistic locking on aforementioned version numbers
- dynamic updates
- cascade is set to all-delete-orphan

That if I update/create a child object, and saveOrUpdate() the parent object, then the version number for each object in the graph is updated, regardless of whether they were dirty or not.

[Note, the working scenario is detaching the objects from the session, and passing them up to a UI layer, and then back again.]

I was wondering whether it is possible to call update on a parent object, and yet only see the dirty child object (and it's version no) updated? Rather than the entire object graph.

Cheers, Owen

this is explained in Hibernate in action. Do you have it?

Unfortunately not. Maybe I'll get my hands on a copy.

Cheers, Owen

Christian and Gavin explained it very well in the book, just get it, you'll learn all you need

Hi Anthony,

I've got the book now. Read the associated sections, and discovered that all I need is to use 'select-before-update' so that the object isn't assummed to be dirty.

No doubt it is a good book, and will probably prove useful. But I don't think I needed to buy the book for what turned out to be a single paragraph.

Maybe next time you could provide the answer, when it's as obvious and simple to communicate as this would have been. Otherwise, people may think you're just trying to improve book sales.

Cheers, Owen

1- i'm not paid by "Hibernate in action" staff, i'm not paid at all, it is only free help here!
2- always giving a small answer to a complex issue is not good
3- for me cascade + versionning + locking is a complex feature.
4- By answering your particular use case, some other users would have used it everytime and select-before-update can be a performance killer.
5- Now you have THE book, you'll learn everything about concurrency, locking, versionning and even more....
6- Tell everybody how Hibernate in Action is a great book ;)


Regards,

Hi Anthony,

I wasn't meaning to agro in my last response, just wanted to point out that 'buy the book' kind of defeats the point of having the forum in some senses.

However, from your response I get the impression the you are suggesting there are alternative solutions. Perhaps I am missing something, but I couldn't see an alternative to 'select-before-update' given what I'm attempting to achieve.

Assuming that I still want to call update on the parent object , and only update the version numbers/data on those objects in the graph that are 'dirty' what other solutions are there?

Cheers, Owen

for update + versionning with detached instances (that is your case), if you don't want the version to be updated when the object has not been updated in the UI, you need 'select-before-update'. But that's the only use case i see.



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And in read-heavy applications (where data modification is negligible) this is mostly useful if you have DB triggers that shouldn't fire, etc.