sub fetchall_arrayref {
    my $slice= shift || [];
    my $mode = ref $slice;
    if ($mode eq 'ARRAY') {
        push @rows, [ @$row ] while($row = $sth->fetch);
    }
    elsif ($mode eq 'HASH') {
        push @rows, $row while ($row = $sth->fetchrow_hashref);
    }
    else { 
        Carp::croak("fetchall_arrayref($mode) invalid") 
    }
    return \@rows;
}