The road to using Mysql

The normal way to produce a website that accesses data from a Mysql database is via the scripting language PHP. I wondered if it were possible to use Perl instead, and found that with the use of a couple of modules, it's not so hard to get started. (Here's a brief introduction to using modules with web programming.
Here's the Perl I wrote (calling the file empnew.cgi). I made sure the program was executable, and placed the file in a directory on my web server (make sure your path points to this directory):


#!/usr/bin/perl
use CGI;
use HTML::Template;
use DBI;
use strict;

my $dsn = 'dbi:mysql:one:localhost:3306:mysql_socket=/opt/lampp/var/mysql/mysqld.sock';
# the database here is called 'one'

my $CGI = CGI->new();
my $user = 'root';
my $pass = 'passwordx';


my $dbh = DBI->connect($dsn, $user, $pass)
or die "Can’t connect to the DB: $DBI::errstr\n";

my $sth = $dbh->prepare("select empno, ename, job, sal from emp order by ename");
$sth->execute;



# Prepare a data structure for HTML::Template
my $rows;
push @{$rows}, $_ while $_ = $sth->fetchrow_hashref();

#
# initiate the template and substitute the values:

my $template = HTML::Template->new(filename => 'empnew.tmpl',
die_on_bad_params => 0, );
# call param to fill in the loop with the loop data by reference.
$template->param(ROWS => $rows);


print $CGI->header();
# print the template
print $template->output();

$dbh->disconnect();


The module CGI deals quickly and efficiently with http headers.

The module HTML::Template that is called, allows you to state the Html layout in a separate file. In our example this calls empnew.tmpl

Code:

There are basically 3 new kinds of tags to be aware of when making a .tmpl file for access by HTML::Template. These are

Code:

The other tags can be standard html formatting stuff. Here's a good introduction to using the HTML::Template

Finally, in order to access data from the Mysql database we need to use the DBI module. You can see from the Perl script that we connect to the database using parameters given (not a good idea from the security pov to have the password in this script in real life - better to bring in as a parameter from a file that can't be seen by public eyes), prepare the sql script, and then execute. For more information on starting with DBI see this tutorial

Once this is setup, it's fairly simple to change the layout by editing the tmpl file directly without needing to change the program code.

I hope this has been of interest! Good luck with your web programming!