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From: "Antony Paul" <antonypaul24@hotmail.com>
To: "Tomcat Users List" <tomcat-user@jakarta.apache.org>
References: <008901c3a1d6$61c883b0$fabafea9@messianic.dyndns.org>
 <Law12-OE56Nj9YsL4lh0001075f@hotmail.com> <3FA62327.FA7F99B5@hager.fr>
Subject: Re: Design advice needed.
Date: Mon, 3 Nov 2003 16:52:26 +0530
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Message-ID: <LAW12-OE63uLn5U9T3T00010923@hotmail.com>

But this requires adding a column to every table.
I found two ways of doing this.
1.  Using time stamp. It requires adding a column to table.
2. Checking data for equality before updating. It requires querying database
again.
Any alternative way.

thanks for the replies

Antony Paul

----- Original Message -----
From: "Jean-Louis" <claussj@hager.fr>
To: "Tomcat Users List" <tomcat-user@jakarta.apache.org>
Sent: Monday, November 03, 2003 3:13 PM
Subject: Re: Design advice needed.


> Hi,
>
> you can use a timestamp and write for example :
> update ...
> where ...
> and timestamp = 'the timestamp read by the select statement and saved in
your application'
>
> And then check the number of rows updated.
>
> Antony Paul a �crit :
>
> > Can u pls mention what is that Oracle feature ?. Reading the data again
is
> > time consuming.
> > ----- Original Message -----
> > From: "Johan Kok" <jkok@messianic.dyndns.org>
> > To: "'Tomcat Users List'" <tomcat-user@jakarta.apache.org>
> > Sent: Monday, November 03, 2003 12:17 PM
> > Subject: RE: Design advice needed.
> >
> > > Anthony,
> > >
> > > Did you consider reading the record without locks, and when an updated
are
> > > made, to take a write-lock, check that the original record are still
the
> > > same and then apply, otherwise fail.
> > >
> > > Your intentions might not work unless all writes are passed through
the
> > > container, as Oracle will not have any control, until a write occurs,
i.e.
> > > you will have to open with read only, and only take out a lock when
you
> > are
> > > going to write, as described above. for safety sake your container
will
> > have
> > > to re-read the data in any case, before commiting, otherwise it may
update
> > > changed data, e.g. updates that are made through other processes or
even
> > > triggers.
> > >
> > > If my memory serves me right, that is something you can do easily with
> > > Oracle (i.e. there's a standard feature implemented), even with Oracle
> > 6/7.
>
> Jean-Louis CLAUSS
>
>
>

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