private function getRelationConfigurationFromTca($key)
    {
        $tca = \Tx_Oelib_Db::getTcaForTable($this->getTableName());

        if (!isset($tca['columns'][$key])) {
            throw new \BadMethodCallException(
                'In the table ' . $this->getTableName() . ', the column ' . $key . ' does not have a TCA entry.',
                1331319627
            );
        }

        return $tca['columns'][$key]['config'];
    }