use strict;
use warnings;

use DBI;

my $dbname   = "test";
my $dbstring = "dbi:Pg:dbname=$dbname";
my $dbuser   = "postgres";
my $dbpwd    = "postgres";

my $dbh = DBI->connect($dbstring, $dbuser, $dbpwd, {AutoCommit => 0})
  || die "connection failed: $DBI::errstr\n";

$dbh->disconnect();