base.py 文件源码

def get_new_connection(self, conn_params):
        connection = Database.connect(**conn_params)

        # self.isolation_level must be set:
        # - after connecting to the database in order to obtain the database's
        #   default when no value is explicitly specified in options.
        # - before calling _set_autocommit() because if autocommit is on, that
        #   will set connection.isolation_level to ISOLATION_LEVEL_AUTOCOMMIT.
        options = self.settings_dict['OPTIONS']
        try:
            self.isolation_level = options['isolation_level']
        except KeyError:
            self.isolation_level = connection.isolation_level
        else:
            # Set the isolation level to the value from OPTIONS.
            if self.isolation_level != connection.isolation_level:
                connection.set_session(isolation_level=self.isolation_level)

        return connection