public function build_director()
 {
     $sql_builder = new SQLBuilder();
     $data = $this->get_data();
     $input = SQLLexical::make_product_list($data['list_product']);
     return $sql_builder->sql_insert('tam_an.product', array('Name', 'Bought', 'Price', 'Unit'))->sql_insert_values_recursive($input)->end_query()->to_string();
 }