[ILUG] Perl / MySQL oddity

[Niall]

On Sat, Apr 22, 2000 at 12:59:19AM +0000, D ONeill wrote:

> You need to post the entire block of source before that can be answered.
> Normally, if you're going to use the assingment variables, you do it right
> after the match statement.  By not assigning the variables right away, you
> risk not having what you expect in the assingment variables.

Yes, I know that, and I referred to it in my original post. What I posted
shows the problem, and my code is not relevant. However, I threw
together a small program which you can cut and paste to show the problem:

#!/usr/bin/perl
#
use DBI;
use strict "vars";
my ($Filename, $title, $dbh);
$dbh = DBI->connect("DBI:mysql:Photocall", "web", "web");
$Filename = "1 Anything at all /WHATEVER";
$Filename =~ m-(\d+ +)(.*)(/WHATEVER)-;
print "backreference 2 is $2\n"; # remove this line to see problem
$title = $dbh->quote($2);
print "Title is $title\n";
# replace with code from block below
$dbh->disconnect;
exit(0);

Of course you'll need to substitute your own values for database, username &
password and to run the above you'll need to be running MySQL and have all
the relevant modules. I don't know if also occurs with any DBI modules
other than DBI:mysql.

When scribbling the above, I noticed a further oddity. I tried to write a
program which showed the problem occurring and then not occurring - the
problem stops occuring once $2 is used before $dbh->quote, even if there are
subsequent matches. If you insert this code where marked above

$Filename = "1 A new thing /WHICHEVER";
$Filename =~ m-(\d+ +)(.*)(/WHICHEVER)-;
$title = $dbh->quote($2);
print "Title is $title\n";

the problem occurs in both places unless the print statement (or a statement
with $2 as an rvalue) is executed, but only one reference to $2 is needed.

Chew on that for the weekend . . . . .


Regards,


Niall  O Broin