2018-7-17日 源碼 閲讀

1、AppConfig 需要了解  目前理解为 注册installed_app使用，可以增加其他一些属性

2、logger 需要进一步学习，用于日志记录，理解log运行流程，特别是handler的使用，切分日志文件，理解其每天按时间记录，保持每天生成日志，删除过期日志。目前打开log日志会报错 ：Resource deadlock avoided ，已关闭日志

3、makemigrations  No Changes Detected 需要寻找原因， 数据库内的表已经删除，且源码内部的migrations文件夹已删除，百度有以下原因：

1. migration folder You need a migrations package in your app.
2. INSTALLED_APPS You need your app to be specified in the INSTALLED_APPS .dict
3. Verbosity start by running makemigrations -v 3 for verbosity. This might shed some light on the problem.
4. Full path In INSTALLED_APPS it is recommended to specify the full module app config path 'apply.apps.MyAppConfig'
5. --settings you might want to make sure the correct settings file is set: manage.py makemigrations --settings mysite.settings
6. specify app name explicitly put the app name in manage.py makemigrations myapp - that narrows down the migrations for the app alone and helps you isolate the problem.

7. model meta check you have the right app_label in your model meta

8. Debug django debug django core script. makemigrations command is pretty much straight forward. Here's how to do it in pycharm. change your script definition accordingly (ex: makemigrations --traceback myapp)