public function toString()
    {
        $sb = 'Criteria:';
        try {

            $params = [];
            $sb .= "\nSQL (may not be complete): ".$this->createSelectSql($params);

            $sb .= "\nParams: ";
            $paramstr = [];
            foreach ($params as $param) {
                $paramstr[] = $param['table'] . '.' . $param['column'] . ' => ' . var_export($param['value'], true);
            }
            $sb .= implode(', ', $paramstr);

        } catch (\Exception $exc) {
            $sb .= '(Error: ' . $exc->getMessage() . ')';
        }

        return $sb;
    }