An ignorant application developer with certain rights. But's a good
interview question and something I could see happening in a development
environment and causing all sorts of havoc.
Jim
"Malcolm Stonebridge" <malc_at_stoneyb.freeserve.co.uk> wrote in message
news:b2p3mn$res$1_at_news7.svr.pol.co.uk...
> Surely if we follow Occam's razor, the simplest explanation is usually the
> correct one (or you should not pad out explanations with complexity if you
> don't need to), then the misunderstood question about mysequence.currval
and
> mysequence.nextval would be the most reasonable/likely explanation. After
> all, what kind of a total plank would insert extra rows into Dual !???
>
> Malcolm
>
> "DA Morgan" <damorgan_at_exesolutions.com> wrote in message
> news:3E50096D.F98CEF4B_at_exesolutions.com...
> > Jim Kennedy wrote:
> >
> > > Daniel,
> > > Sure we don't know what the interviewer was thinking, but this the
type
> of
> > > question that one might use to dig for experience and problem solving.
> It
> > > is likely the sequence question alone is fairly simple and
> straightforward
> > > (one would hope), but by combining it with this "odd" behavior (Hmm,
got
> 2
> > > rows back from dual.) The interviewer is asking both about sequences,
> what
> > > dual is, and why might it be acting unusual.(have 2 rows) It is the
> type of
> > > thing that would happen in real life (some bozo did an insert into
dual
> and
> > > now it has 2 rows, and is creating all sorts of havoc.)
> > > Jim
> > > "DA Morgan" <damorgan_at_exesolutions.com> wrote in message
> > > news:3E4FD982.EDE9B0B0_at_exesolutions.com...
> > > > Jim Kennedy wrote:
> > > >
> > > > > I think the question was aimed at finding out that someone had
added
> a
> > > row
> > > > > to dual and that will cause problems with applications that use
dual
> > > > > expecting 1 row.
> > > > > Jim
> > > > >
> > > > > --
> > > > > Replace part of the email address:
> kennedy-down_with_spammers_at_attbi.com
> > > > > with family. Remove the negative part, keep the minus sign. You
> can
> > > figure
> > > > > it out.
> > > > > <Kenneth Koenraadt> wrote in message
> > > > > news:3e4f8b9d.629164_at_news.inet.tele.dk...
> > > > > > On Sat, 15 Feb 2003 18:17:04 GMT, "Ryan" <rgaffuri_at_cox.net>
wrote:
> > > > > >
> > > > > > >I got a trick question in an interview and I dont know if what
I
> said
> > > was
> > > > > > >write. It was a written exam so I couldnt ask.
> > > > > > >
> > > > > > >Someone does
> > > > > > >
> > > > > > >select sequence.nextval
> > > > > > > from dual;
> > > > > > >
> > > > > > >you get two sequence numbers back. All I could think of was
that
> > > someone
> > > > > > >inserted a second row into dual.
> > > > > > >
> > > > > > >Could any other reason lead to two sequence numbers being
> returned?
> > > > > > >
> > > > > > >
> > > > > >
> > > > > > Hi Ryan,
> > > > > >
> > > > > > Maybe the question was just awkwardly asked. I guess they wanted
> to
> > > > > > test if you knew about both sequence.NEXTVAL and
sequence.CURRVAL
> :
> > > > > >
> > > > > > Nextval is returned from the statement. No doubt. And if you
> > > > > > afterwards do :
> > > > > >
> > > > > > select sequence.currval from dual;
> > > > > >
> > > > > > You get the same value again. In that sense, you can say that
you
> get
> > > > > > 2 values at your service, *because* :
> > > > > >
> > > > > > If you start a user session and have a sequence myseq and issue
:
> > > > > >
> > > > > > select myseq.currval from dual;
> > > > > >
> > > > > > You get ORA-08002: Sequence MYSEQ.CURRVAL not yet defined.....
> > > > > >
> > > > > > You have to invoke NEXTVAL by *first* calling
> > > > > >
> > > > > > select myseq.nextval from dual;
> > > > > >
> > > > > > and *then* you can do ;
> > > > > >
> > > > > > select myseq.currval from dual;
> > > > > >
> > > > > > So "select sequence.nextval from dual" does, make another value
> > > > > > avilable : sequence.currval.
> > > > > >
> > > > > > Interviewers trying to make tricky questions, are often tricking
> > > > > > themselves instead....
> > > > > >
> > > > > > - Kenneth Koenraadt
> > > > > >
> > > > > >
> > > > > >
> > > >
> > > > As opposed to SELECT COUNT(*) FROM dual;?
> > > >
> > > > The question is reasonable as a way of understanding someone's
> > > understanding of
> > > > dual and how sequences work. Trying to psychoanalyze those that put
> > > together the
> > > > questions may not lead to a lot of clarity as we'll likely never
know
> why
> > > any
> > > > question ends up on one of these things.
> > > >
> > > > What I find more amazing is the questions and answers (especially on
> the
> > > OCP)
> > > > that are clearly incorrect.
> > > >
> > > > Daniel Morgan
> > > >
> >
> > Hope you didn't misunderstand ... I think it is a great question and
plan
> to add
> > it to my repetoire for just the reasons you cite.
> >
> > Daniel Morgan
> >
>
>
Received on Sun Feb 16 2003 - 16:53:13 CST
