Here's how I do it. This way you don't have to keep track of which
field(s) may be null.
my $slct_insp = $dbh->prepare("select * from tqosinsptrk
where chgdttm < current - 10 units minute
and procdttm is null order by insptrkrwd asc") ||
die cleanup("prepare select tqosinsptrk");
undef $rv;
undef $ref;
$rv = $slct_insp->execute || die cleanup("execute select tqosinsptrk");
$ref = $slct_insp->fetchall_arrayref() || die cleanup("fetchall select tqosinspt
rk");
open(OUT,">$dtafile2") || die cleanup("open insp outfile");
foreach my $row (@$ref) {
$out = join("|",map { chkinit($_) } @$row) || die cleanup("join insp");
print OUT $out,"|\n" || die cleanup("print insp outfile");
$upd_insp->execute(@$row[0]) || die cleanup("execute update insptrk");
}
close(OUT) || die cleanup("close insp file");
##########################################################################
# SUBROUTINE: CHKINIT #
##########################################################################
sub chkinit {
my ($fld) =@_;
if ( ! defined $fld ) {
$fld='';
}
return $fld;
}
>
> But if what you want to get (and print) is "", would this (using NVL
> in the select statement) work? Or would "" returned from the database
> get interpreted by the DBI (or maybe by Perl itself) as undef?
>
> Here's my clunky workaround for avoiding warnings about undef values (when
> I don't want to just say "no warnings 'uninitialized';" in that block):
>
> while ( $sth->fetch )
> {
> for my $each ( $field1, $field2 ) #-- any fields I'm fetching that might be null
> {
> $each ||= "";
> }
> print OUT join "|", ( $field1, $field2, $field3 ), "\n";
> }
>
> Mitch Helle-Morrissey's idea seems much more elegant.
>
> --
> David Dierauer
> Database Programmer
> CoreComm
>
> On Fri, 4 Jan 2002, Morris Paterson wrote:
>
> > why not use a NVL in your select staetment?
> >
> > Mitch Helle-Morrissey wrote:
> >
> > > Is there any way to have DBI return NULL database values as something other
> > > than Perl undef? It's a pain if you're printing out a bunch of columns
> > > without examining the values because printing an undef generates warnings.
> > > I wrote my own function to map undefs to something else, but I was thinking
> > > it would be nice to have an attribute of how NULL database values will be
> > > returned to Perl. Maybe something like:
> > >
> > > $dbh->{NULL_VALUE} = '';
> > > $dbh->{NULL_VALUE} = 'NULL';
> > > $dbh->{NULL_VALUE} = undef; # current behavior
>
>
--
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