function category_get_by_id($id)
{
    $result = sql_do('SELECT id_cat,name_cat,index,parent,valid_cat FROM categories WHERE id_cat=\'' . int($id) . '\'');
    if ($result->numRows() != 1) {
        return 0;
    }
    $row = $result->fetchRow();
    $cat = new Category();
    $cat->set_id_cat($row[0]);
    $cat->set_name_cat($row[1]);
    $cat->set_index($row[2]);
    $cat->set_parent($row[3]);
    $cat->set_valid_cat($row[4]);
    return $cat;
}