django中执行py报错Requested setting DEFAULT_INDEX_TABLESPACE, but settings are not configured

django代码下面直接run的时候报错：

django.core.exceptions.ImproperlyConfigured: Requested setting DEFAULT_INDEX_TABLESPACE, but settings are not configured. You must either define the environment variable DJANGO_SETTINGS_MODULE or call settings.configure() before accessing settings.

查了下，解决办法是在模块前面添加：

import os
os.environ.update({"DJANGO_SETTINGS_MODULE": "config.settings"})