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Help Record Lock?

Patrick Wang
Greenhorn

Joined: Oct 15, 2001
Posts: 20
Hi,
I have some question about client lock?
From complete Java 2 certification book, it talked about 3 different method of record locking?
1) Active Client-- locking record when row highlighted
2) On demand Client-- lock is integral to all add/delete/modify operations.
My question is when you use on demand client locking, how can you
prevent dirty/update, say one client update record N, released the lock, then the second client update the same record N, overwrite the update that the previous client made. I know you can have a timestamp field lastupdatetime for each record so
the second client update will fail. But it seems a little complex, just curious is there any better clean design out there
resolve this issue?
Thx
Pat
Peter den Haan
author
Ranch Hand

Joined: Apr 20, 2000
Posts: 3252
Well spotted. The solution is a lot simpler, fortunately; after locking the record, re-read it so you have fresh data. Then, if the necessary seats are still available, modify the record and write it back.
- Peter
 
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