Hibernate version: 2.1.7

hi,

i'm trying to implement an optimistic locking with the following characteristics:
1. i'm using version columns
2. only the application should check for version conflicts
3. hibernate should update the version columns when updates occur, but not check for conflicts.

i know how to tell hibernate that i'm using a version column.
i know how to make the application check the version.
but how do i achieve the behaviour described above under 3.

thanks
martin

Why would you want the application to check the version and not Hibernate ? That would leave the application vulnerable to overwriting of updates since it would be possible for one process to update the data after your version-check but before the database update is comitted.

That's why the method of appending the "and version_attribute = ?" to the update or delete statement is used.

If you really do want Hibernate to not check for conflicts, then don't use a <version> attribute and you can do it all yourself. (Not that I think this makes much sense)

i agree with the previous reader that it doesn't make much sense to let the application do the version checking. however if you really want it, i think you can write an interceptor and manipulate the version number in the onSave method.

hi pksiv,

thanks for the fast answer.



as i understand it hibernate checks for version conflicts on flush-time,
when he is doing the actual updates (by adding a version attribute in the where clause). if the check fails hibernate delivers a staleobjectexception.

the problem wih this behaviour is that hibernate stops with checking after the first conflict it has found. but i need infos (class and object-id) about all stale objects that are flushed at the end of my application transaction. i want to deliver these infos to my clients in order to give them the opportunity to react, e. g. merge.



this is no problem as i can read the current version with select-for-update before checking it.



that's what i expected.
but this chapter
http://www.hibernate.org/hib_docs/v3/re ... tic-manual
definitely gave me the impression that the behaviour i described above can be realized with hibernate. the documentation is a little confusing at that point.

again thanks.

bye
martin

hi weigingh,



thanks for that point.
i do not know anything about interecptors, but this will change soon.
i can imagine that is is probably an elegant way for implementing a version update by application.

bye
martin

Here is a thread on these and other issues. There are many threads wondering how to recover from Hibernate-detected version conflicts. I'm trying to centralize discussion there.