#!/usr/bin/perl

use warnings;
use strict;

use constant DSN => 'DBI:mysql:database=test';
use constant DBUSER => 'user';
use constant DBPASS => 'pass';

use DBI;

our $dbh = DBI->connect(DSN, DBUSER, DBPASS, {
                                AutoCommit => 0,
                                RaiseError => 1,
                        } )
  or die "Couldn't connect to database: ",$DBI::errstr;

# Create the message and get the ID

my $sth = $dbh->prepare("SELECT a FROM transtest");
$sth->execute();
my $row = $sth->fetchrow_hashref;
warn "$$ a=$row->{a}\n";
sleep(5);
$dbh->do("UPDATE transtest SET a = ?",undef,$row->{a}+1);
warn "$$ done\n";