public function setBaseConfig(array $config)
    {
        parent::setBaseConfig($config);

        if (!$config['group_column']) {
            throw new DcGeneralException(__CLASS__ . ' needs a grouping column.', 1);
        }
        $this->strGroupCol = $config['group_column'];

        if ($config['sort_column']) {
            $this->strSortCol = $config['sort_column'];
        }
    }