Re: Why is $sth->rows() uninitialized?

It's possible that the value of literal zero being returned is being interpreted as uninitialized
by Perl.

You should try something like this:

if (! defined($sth->rows()) || $sth->rows() == 0)) {
print STDERR "Duplicate item found at line $ln: $_\n";
}


--- KEVIN ZEMBOWER <[email protected]> wrote:
> Thanks to the suggestions of Greg and others, I was able to use $sth-rows() to determine if a
> record was present or not in my table. Thanks, Greg. The section of code I used successfully is:
>       $kwsth->execute($_) or warn "Problem with execute: $DBI::errstr\n";
>       
>       if ($kwsth->rows() == 0) { 
>          print "Keyword $_ not found " if $debug; 
>          $inskwsth->execute($_);
>          $keywordid = $dbh->{'mysql_insertid'};
>          print "NEW id = $keywordid\n" if $debug;
>    
>       } else { # If the keyword doesn't already exist in the table, else...
>       
>          $keywordid = $kwsth->fetchrow_array or warn "Problem with fetch: $DBI::errstr\n";
>          print "Keyword ID: $keywordid\n" if $debug;
>       } # else if the keyword DOES exist in the table already
> 
> 
> Now I'm trying to apply this to another program in an almost identical fashion, and don't
> understand why I'm getting an error. The section of code is:
>    my $sth = $dbh->prepare("SELECT baseitemid FROM langversions WHERE baseitemid =? AND
> langid=?");
>    $sth->execute($baseitemid, $langid);
>    
>    if ($sth->rows() == 0) { #THIS is line 70
>       print STDERR "Duplicate item found at line $ln: $_\n";
>    } else {
>       my $sth = $dbh->prepare("INSERT INTO langversions (baseitemid, langid, title, cost,
> available) VALUES (?, ?, ?, ?, ?)" ) or die "Can't prepare statement: $DBI::errstr";
>       $sth->execute($baseitemid, $langid, $title, $cost, $available)
>          or die "Can't execute statement: $DBI::errstr";
>    } # else if there was no duplicate item
> 
> When I execute this with trace(2) set, I get this section of the output:
>     <- prepare= DBI::st=HASH(0x828b1f0) at loadInventory.pl line 67
>     -> execute for DBD::mysql::st (DBI::st=HASH(0x828b1f0)~0x81e27e0 '1' '1')
>     -> dbd_st_execute for 0828b220
>       Binding parameters: SELECT baseitemid FROM langversions WHERE baseitemid ='1' AND
> langid='1'
>     <- dbd_st_execute 0 rows
>     <- execute= '0E0' at loadInventory.pl line 68
>     -> rows for DBD::mysql::st (DBI::st=HASH(0x828b1f0)~0x81e27e0)
>     <- rows= '0' at loadInventory.pl line 70
> Use of uninitialized value in concatenation (.) or string at ./loadInventory.pl line 70.
> Duplicate item found at line 1: 
> 
> The last line is my STDERR output. The previous line is an error message. The trace() output
> seems to show rows() being set to '0' at line 70,  which is "if ($sth->rows() == 0) {".
> 
> I don't understand perl says $sth->rows() isn't initialized, when it seems to be set to zero,
> and why this system isn't working in this program, but seems to work fine in my other one.
> 
> Thanks for any light you can shed on this problem.
> 
> -Kevin
> 
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