You can reduce three of your lines to one by using selectall_arrayref() like so:

my $results = $dbh->selectall_arrayref(
   "SELECT * FROM shop_items", { Slice => {} }
);
foreach my $hash_ref (@$results)
{
   # blah
}
[download]

If you want to write it as a subroutine, this would work:

sub fetch_data
{
    my $dbh = shift;
    return $dbh->selectall_arrayref(
       "SELECT * FROM shop_items", { Slice => {} }
    );
}
[download]

Then you could call it like this:

foreach my $hash_ref (@{&fetch_data($dbh)})
{
    # blah
}
[download]

-Matt