public function getQueryPartForAdditionalFields(array $fieldValues)
    {
        $queryForSet = '';
        $queryForExecute = '';

        $queryBuilder = Db::getQueryBuilder('tx_kesearch_index');

        foreach ($this->additionalFields as $value) {
            $queryForSet .= ', @' . $value . ' = ' . $queryBuilder->quote($fieldValues[$value], \PDO::PARAM_STR);
            $queryForExecute .= ', @' . $value;
        }
        return array('set' => $queryForSet, 'execute' => $queryForExecute);
    }