private function setDBorSchema($db_name)
    {
        if (strtolower($this->connectionType($db_name)) === 'postgres9') {
            $adapter = $this->getAdapter($this->connectionType($db_name));
            $selectDbQuery = $adapter->useNamedDB($db_name);
            return $this->connections[$db_name]->Execute($selectDbQuery);
        }

        return $this->connections[$db_name]->SelectDB($db_name);
    }