Re: no sql-select after sql-update?

["Fred Kulack" <kulack@xxxxxxxxxx>]

On 10/12/2001 at 09:02:09 AM, java400-l-admin@midrange.com wrote:
Please read mail 'URGENT please : Locked records'  also.

The record is available when using 'select...' statement when I execute the
methods from within VAJAVA, not when executed from webapp...
The intention is to 'lock' for updating only!
--- end of excerpt ---

I don't save email from java400-l so can't look back in history.
Is there an archive somewhere?

Not too sure how to answer this one...
Lets see if I can try a couple things and hit the mark...


If you've got a row locked for update, and the isolation level
of the reader says that you _don't_ want to get data that could
possibly change or be out of date (repeatable_read), then you're
simply not going to be able to read it.


Perhaps you want to make the reader run with a lower isolation level
(read_uncomitted) because it sounds like it can tolerate reading
'out of date' data? i.e. rows that the other guy has locked for
update (or has actually updated already that may roll back) .


However, perhaps you want the updater to run with a higher isolation level
(repeatable read) because it will be the one reading, then later
updating the row. It wouldn't want anyone to be mucking with the row
between the read and the update of that row.

1) do the query with statement 1
2) fetch/read the row
blah blah blah .... processing
3) update the row





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Fred A. Kulack  -  AS/400e  Java and Java DB2 access, Jdbc, JTA, etc...
IBM in Rochester, MN  (Phone: 507.253.5982   T/L 553-5982)
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