#!/usr/bin/perl -w
  use strict;
  use DBI;

  my $dbh = DBI->connect('DBI:mysql:genome', 'u', 'p') || die $DBI::errstr;
  my $sth = $dbh->prepare("SELECT foo FROM bar WHERE baz = 4"); 
  $sth->execute() || die $DBI::errstr;
  while (my ($foo) = $sth->fetchrow()) {
    # Do something with $foo eg:
    print "foo = $foo\n";
  }

  $sth->finish();
  $dbh->disconnect() || warn $DBI::errstr;