protected function createSecondaryIndexes()
    {
        $this->addIndex(
            new CNabuDataObjectListIndex($this, 'nb_site_target_section_key', 'nb_site_target_section_order', self::INDEX_KEY)
        );
        $this->addIndex(
            new CNabuDataObjectListIndex($this, 'nb_site_target_section_order', 'nb_site_target_section_order', self::INDEX_ORDER)
        );
    }