#!/usr/bin/perl
use warnings;
use strict;

use DBI;
use Data::Dumper;

my $db = DBI->connect("dbi:$driver:", q(), q());

my %hash;
my $sth = $db->prepare('select week, month, workperiod from tablename');
$sth->execute;
while (my ($week, $month, $workperiod) = $sth->fetchrow_array) {
    $hash{$week} = [$month, $workperiod];
}
print Dumper \%hash;