All are examples of why using RaiseError is a good idea!
Tim.
On Sun, Sep 23, 2001 at 12:27:31PM -0400, Sterin, Ilya wrote:
>
>
> > -----Original Message-----
> > From: Steven Vetzal [mailto:[EMAIL PROTECTED]]
> > Sent: Sunday, September 23, 2001 8:06 AM
> > To: [EMAIL PROTECTED]; [EMAIL PROTECTED]
> > Subject: RE: Avoid Error if no results
> >
> >
> > Ahh yes, what I commonly call the "null vs. 0 gank"... The perl syntax
> > allowing you to run alternate code during an assignment if the return
> > value of the assignment is 0 OR undef.
> >
> > I'm assuming you only want to call dbError if the result from
> > selectrow_array() is undef (an actual error)
>
>
> No, it doesn't necessarily mean an error. It returns undef also if there
> are no rows to fetch, when your query did not produce results. That is the
> reason you don't use (|| ....) on the fetch method, unless you specifically
> want it.
>
>
>
> and not if the result from
> > selectrow_array() was that count() == 0.
> >
> > You should replace:
> >
> > $expire = $dbh->selectrow_array($sqlquery) or dbError();
> >
> > with 2 lines:
> >
> > $expire = $dbh->selectrow_array($sqlquery);
> > dbError() unless defined($expire);
>
>
> What happens if there is something returned, but the first column is NULL,
> which will set $expire to undef? This will not produce the wanted results,
> see perldoc DBI.
>
> Ilya
>
> >
> > IMHO just one of those places it's best _not_ to use a nice compact
> > perlism to reduce the size of your code.
> >
> > Steve
> >
> >
> >
> > > -----Original Message-----
> > > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
> > > Sent: Saturday, September 22, 2001 7:38 PM
> > > To: [EMAIL PROTECTED]
> > > Subject: Avoid Error if no results
> > >
> > >
> > > Hi All,
> > >
> > > this one seems to puzzle me on how to avoid an unnecessary db
> > > error. I need to
> > > run a tally count on a couple tables, and if there isn't any
> > > data in the table
> > > it displays the dbError, altho there isn't technical any
> > > syntax error in the
> > > query other then no return or results.
> > >
> > > my $active = 0;
> > > my $expire = 0;
> > >
> > > $sqlquery = qq|SELECT COUNT(m.memid) FROM members m,payhistory p
> > > WHERE p.active = 'Y' AND p.memid = m.memid|;
> > > $active = $dbh->selectrow_array($sqlquery) or dbError();
> > >
> > > $sqlquery = qq|SELECT COUNT(*) FROM expired WHERE expdate <
> > > CURDATE()|;
> > > $expire = $dbh->selectrow_array($sqlquery) or dbError();
> > >
> > > Is this way to avoid the dbError() if the query returns no
> > > results(which would
> > > indicate a '0' tally.
> > >
> > > thx's
> > >
> > > Mike(mickalo)Blezien
> > > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> > > Thunder Rain Internet Publishing
> > > Providing Internet Solutions that work!
> > > http://www.thunder-rain.com
> > > Tel: 1(225)686-2002
> > > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> > >
> > >
