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
>
>
>
Received on Sun Feb 16 2003 - 10:12:04 CST
