Is the object lock by an other user?

Fr@ncky · **Posted:** Tue Nov 23, 2004 11:18 am

Hibernate version:
2.1.4

Hello,

Is there possible to know if an object ist currently used by another person ?

christian · **Posted:** Tue Nov 23, 2004 11:46 am

What?

Fr@ncky · **Posted:** Tue Nov 23, 2004 11:54 am

Excuse me, my english is not so good, so I try to explain my problem:

I want to know how hibernate can handle the lock of records ?
If I have a user A who is currently editing a record, who can I block that record from the other user ?

Tx

christian · **Posted:** Tue Nov 23, 2004 11:57 am

You usually don't do such a thing (since it would require long running database connections with open database locks), a much better option is optimistic concurrency control (thats what Hibernate offers, in all other aspects, it relies on the database system). Almost every documentation about transaction handling and locking should have the information about both.

snpesnpe · **Joined:** Sat Jun 12, 2004 4:49 pm **Posts:** 915

session.lock(...) or versioning - versioning work if You update database with hibernate only and
session.lock work always

regards

christian · **Posted:** Wed Nov 24, 2004 3:56 am

Wrong, you can use optimistic-lock="all" and compare all columns. Versioning works just fine if many applications access the same database, even without version or timestamp columns.

snpesnpe · **Joined:** Sat Jun 12, 2004 4:49 pm **Posts:** 915

Christian,
It is fine, but what if I want that nobody touch row until I finish and I haven't changes yet

regrads

christian · **Posted:** Wed Nov 24, 2004 7:36 am

You either keep the database connection open and hold a pessimistic lock in the database or you implement something like an "offline pessimistic lock" yourself. Martin Fowler has it in his patterns collection.

snpesnpe · **Joined:** Sat Jun 12, 2004 4:49 pm **Posts:** 915

Christian,
It help me true database true."offline pessimistic lock" don't help for another application
Your versioning is great for every case except big oltp application with a lot updates

I make swing application and I want that when user type one character in form application/database lock row and another user have notification when she/he type first character.
Versioning can help and with this case:
scenario :
user A can populate row and wait;lock doesn't exist
user B change same row and commit
user A change and commit and without versioning he rewrite data form user B

Oracle tools (developer) have this problem.

I will set versioning (probably optimistic-lock="all") and pure database lock for oltp
However, versioning don't help for legacy application.
Hibernate have great locking for hibernate only, but there isn't complete correct solution for
legacy application

regards