Groups > comp.lang.java.programmer > #27001

Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys

Date	2013-12-20 16:29 +0000
From	lipska the kat <"lipskathekat at yahoo dot co dot uk">
Organization	Trollbusters 3
Newsgroups	comp.lang.java.programmer
Subject	Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys
References	<slrnlb8jo8.42s.avl@gamma.logic.tuwien.ac.at>
Message-ID	<b7OdnaX-95fk7SnPnZ2dnUVZ8uWdnZ2d@bt.com> (permalink)

Show all headers | View raw

On 20/12/13 14:07, Andreas Leitgeb wrote:
> I have to write code to execute runtime-specified SQL-statements,
> and there are two things that I wasn't able to understand from reading
> the javadocs:
>
> 1.)
> When would one call .getMoreResults() on a statement instead of just
> another rs.next() on the first one (obtained from stmnt.getResultSet())?
> Are these equivalent, or is there really a concept of multiple ResultSets,
> each of which has its own independent set of rows?

IIRC multiple ResultSet[s] can be returned from a stored procedure, in 
this case you would need to iterate over the ResultSet[s] using the 
method getResultSet() to get the first results and getMoreResults() to 
check if there are more results. If there are, calling getResultSet() 
again would return the next results. I've never seen a single sql 
statement that would return multiple result sets but this doesn't mean 
it's not possible (obviously)

> 2.)
> As I don't know the statement beforehand, I can't decide at coding
> time, if it might be an "insert"
> eventually returning a serial key,
> and thusly requiring the argument RETURN_GENERATED_KEYS), or a select
> that will need cursor-like treatment such as passing resultSetType,
> resultSetConcurrency and resultSetHoldability flags.
>
> How would I tell the JDBC engine, that if it is a select then it
> should pass certain flags, and if it is an insert, then I would be
> interested in the generated keys?  prepareStatement() doesn't seem to
> have an overload to accept both variants.

You would do this in Java, surely. Use some abstract factory type 
mechanism to generate a suitable class depending on the type of query.
I can't immediately see a way of doing this without identifying the 
'type' of the statement before it's executed.

> Finally, why isn't RETURN_GENERATED_KEYS the default, anyway?

[guess]Because keys aren't always generated perhaps?

> Seasonal Greetings, and thanks in advance
>

-- 
Lipska the Kat©: Troll hunter, sandbox destroyer,
treacherous feline and farscape dreamer of Aeryn Sun
GNU/Linux user #560883 - http://www.linuxcounter.net

Thread

JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2013-12-20 14:07 +0000
  Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys lipska the kat <"lipskathekat at yahoo dot co dot uk"> - 2013-12-20 16:29 +0000
    Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Andreas Leitgeb <avl@auth.logic.tuwien.ac.at> - 2014-03-05 14:10 +0000
      Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys lipska the kat <lipskathekat@example.com> - 2014-03-05 20:34 +0000
        Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Andreas Leitgeb <avl@auth.logic.tuwien.ac.at> - 2014-03-11 15:04 +0000
      Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Arne Vajhøj <arne@vajhoej.dk> - 2014-03-11 20:02 -0400
        Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Andreas Leitgeb <avl@auth.logic.tuwien.ac.at> - 2014-03-12 00:13 +0000
  Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Arne Vajhøj <arne@vajhoej.dk> - 2013-12-20 19:08 -0500
    Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Robert Klemme <shortcutter@googlemail.com> - 2013-12-21 10:15 +0100
      Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Arne Vajhøj <arne@vajhoej.dk> - 2013-12-21 10:59 -0500
        Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Robert Klemme <shortcutter@googlemail.com> - 2013-12-21 17:14 +0100
          Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Arne Vajhøj <arne@vajhoej.dk> - 2013-12-21 12:19 -0500
    Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-12-21 14:59 -0400
      Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Arne Vajhøj <arne@vajhoej.dk> - 2013-12-21 15:04 -0500
        Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-12-21 18:56 -0400
          Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Arne Vajhøj <arne@vajhoej.dk> - 2013-12-21 18:33 -0500
            Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2013-12-22 11:24 +0000
  Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Arne Vajhøj <arne@vajhoej.dk> - 2013-12-20 19:14 -0500
    Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2013-12-21 09:43 +0000
      Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Joerg Meier <joergmmeier@arcor.de> - 2013-12-21 11:59 +0100
      Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Arne Vajhøj <arne@vajhoej.dk> - 2013-12-21 09:15 -0500
        Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2013-12-21 21:43 +0000
          Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Arne Vajhøj <arne@vajhoej.dk> - 2013-12-21 17:34 -0500
            Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2013-12-22 00:47 +0000
              Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Arne Vajhøj <arne@vajhoej.dk> - 2013-12-21 20:10 -0500
                Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Arne Vajhøj <arne@vajhoej.dk> - 2013-12-21 22:45 -0500
                Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2013-12-22 10:59 +0000
                Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Arne Vajhøj <arne@vajhoej.dk> - 2013-12-22 20:09 -0500
                Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2013-12-22 11:08 +0000
    Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Robert Klemme <shortcutter@googlemail.com> - 2013-12-21 11:46 +0100
      Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Arne Vajhøj <arne@vajhoej.dk> - 2013-12-21 13:44 -0500
  Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys firstsql@gmail.com - 2014-03-12 20:23 -0700
    Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Arne Vajhøj <arne@vajhoej.dk> - 2014-05-11 22:10 -0400
      Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Marcel Müller <news.5.maazl@spamgourmet.org> - 2014-05-12 18:29 +0200
        Re: JDBC: getMoreResults() versus rs.next() & autoGeneratedKeys Arne Vajhøj <arne@vajhoej.dk> - 2014-05-13 20:43 -0400

csiph-web