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From Bryan Pendleton <bpendle...@amberpoint.com>
Subject Re: Subject: Detectability of updates in DRDA
Date Tue, 07 Mar 2006 23:58:11 GMT
Dag H. Wanvik wrote:
> Hopefully, we should not even need a separate round-trip, but get info
> back with the row data (perhaps via a warning?), so the client would
> always be aware if a row had been updated as soon as it got it from
> server.

Frankly, my head is spinning trying to think about this. With all the
various combinations of "own" updates versus "others" updates, transaction
isolation levels, implicit and explicit rowsets, etc., this seems like
a horribly complicated behavior to try to explain to a user.

I tried looking at the docs for a couple of other DB vendors, and they
were full of lots of complex language about when the rowUpdated() method
would and would not detect an actual update. Some vendors seemed to say
that rowUpdated only detects updates made by others; some seemed to say
that it only detects updates made by this result set; some just punted
and said they don't support the method.

For example:
http://www.lc.leidenuniv.nl/awcourse/oracle/java.920/a96654/resltset.htm#1020514
http://www.ipd.uka.de/~oosem/mobiledb/pb/docs/server_embedded/html/htmlfiles/dev_tutorial2.html

Do we know anything about how actual applications use this method? Since
I've never tried to use it myself, I don't think I can contribute much
to the discussion about what might or might not be an acceptable implementation.

thanks,

bryan



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