use CGI;
use strict;
use DBI;
use CGI::Carp qw(fatalsToBrowser); # gives detailed errors

my $hostname= "sample.oracle.com";
my $sid="MYSID"; 
my $port = "1521";
my $username = "user";
my $password = 'pass';

my $dbh;
$dbh = DBI->connect("dbi:Oracle:host=$hostname;sid=$sid", $username, $password) or die "connect failed: ". DBI->errstr() unless $dbh;