You have 18 unapplied migration(s). Your project may not work properly until you apply the migration

   成功解决错误：You have 18 unapplied migration(s). Your project may not work properly until you apply the migrations for app(s): admin, auth, contenttypes, sessions.Run 'python manage.py migrate' to apply them. 

  错误的现象是什么，为什么会发生这个错误，怎么解决呢。本文为你详细解释。

目录

一、错误现象

二、错误原因分析

三、解决方法

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