private function ensureIndexNameAttIdLanguage()
    {
        if (!($this->database->tableExists('tl_metamodel_translatedurl'))) {
            return;
        }

        // Renamed in 2.0.0-alpha2 (due to database.sql => dca movement).
        if (!$this->database->indexExists('att_lang', 'tl_metamodel_translatedurl', true)) {
            return;
        }
        $this->database->execute(
            'ALTER TABLE `tl_metamodel_translatedurl` DROP INDEX `att_lang`;'
        );
        $this->database->execute(
            'ALTER TABLE `tl_metamodel_translatedurl` ADD KEY `att_id_language` (`att_id`, `language`);'
        );
    }