Re: streaming result sets: progress

Thanks Barry
I work with Oracle JDeveloper and I can't mimic cross transaction
(access to database work JDeveloper and JDev work with Oracle, DB2,
MS SQL and any SQL 92 compliant database).
I hope that cursor that span transaction will be soon

regards
Haris Peco
On Monday 18 November 2002 05:54 pm, Barry Lind wrote:
> Haris,
>
> I understand your problem. But unless the database supports cursors
> that span transactions, I don't see any solution for you, other than to
> issue multiple sql statements to mimic cross transaction queries in your
> application.
>
> --Barry
>
> Haris Peco wrote:
> > On Monday 18 November 2002 05:14 pm, Barry Lind wrote:
> >>Nic,
> >>
> >>Here are my thoughts on this topic.
> >>
> >>1) Since the server doesn't support cursors across transactions, I don't
> >>think the driver should either. In fact in jdbc3 the DatabaseMetaData
> >>object has a supportsResultSetHoldability() method that explicitly lets
> >>the driver tell the application what is does/doesn't support in this
> >> area.
> >>
> >>I think running multiple sql statements to mimic this behavior is a very
> >>bad idea. Since the select statements will run at different times they
> >>will return different data (since they will pick up commited changes
> >>between runs), and if you don't include an order by the results are
> >>completely unpredictable. If someone wants this very unpredictable
> >>behavior they can issue the multiple statements themselves.
> >>
> >>2) I think the use of cursors should be optional. In fact since most
> >>queries don't need them since most queries return a small number of rows
> >>, I think the use of cursors needs to be turned on. I think there
> >>should be two ways to do this: the first is by setting the fetchSize()
> >>and the second would be a jdbc url parameter.
> >>
> >>3) I think the transaction characteristics of the current patch are just
> >>fine and conform to the jdbc specification. The code should
> >>automatically close the resultset when a commit occurs. One thing that
> >>will be confusing is that noncursor based result sets will work accross
> >>commits, but cursor based ones won't. But I think that is reasonable.
> >
> > My problem :
> > master-detail
> > I select one from many rows master with cursor (big table and only this
> > is possible) - In detail I do change and commit (or rollback)
> > My select is lost.
> > How can I do that ?
> >
> >>Nic Ferrier wrote:
> >>>Message-ID: <87fztyexea(dot)fsf(at)pooh-sticks-bridge(dot)tapsellferrier(dot)co(dot)uk>
> >>>Lines: 24
> >>>MIME-Version: 1.0
> >>>Content-Type: text/plain; charset=us-ascii
> >>>--text follows this line--
> >>>
> >>>Haris Peco <snpe(at)snpe(dot)co(dot)yu> writes:
> >>>>I have tried.
> >>>>DatabaseMetaData is fine, but ResultSet.[get|set]FetchSize don't
> >>>>work
> >>>
> >>>What error do you get?
> >>>
> >>>>Prepared command don't work, but my greatest problem are trasnaction
> >>>>I hope that cursor in 7.4 will be out of a transaction
> >>>
> >>>I don't think there's much I can do about the cursor problem.
> >>>
> >>>>Can Yoy yet another :
> >>>>set driver's flag btw jdbc:pgsql:...?cursor=yes
> >>>>for use cursor or old way
> >>>
> >>>What does everyone else think? Is a system doing a different query
> >>>each time worth looking into?
> >>>
> >>>
> >>>Nic
> >>>
> >>>
> >>>---------------------------(end of broadcast)---------------------------
> >>>TIP 5: Have you checked our extensive FAQ?
> >>>
> >>>http://www.postgresql.org/users-lounge/docs/faq.html
> >>
> >>---------------------------(end of broadcast)---------------------------
> >>TIP 6: Have you searched our list archives?
> >>
> >>http://archives.postgresql.org