django如何更新数据库字段并与数据库保持同步？

关键步骤：

1. 第一步： 执行：python manage.py makemigrations 你的项目名称

2. 第二步：它会提示你选1还是2，这里因为添加字段，所以选1

3. 第三步：出现>>>这个，直接输入这个''

4. 第四步： 执行：python manage.py migrate

5. 第五步：运行项目：python manage.py runserver 本机ip:8000

   (.venv) PS D:\python_workpace\django_xitong_shezhi\pythonProject\myproject> python manage.py makemigrations myproject
   It is impossible to add a non-nullable field 'title_field22' to yingyongguanli without specifying a default. This is because the database needs something to populate existing rows.
   Please select a fix:
   2) Quit and manually define a default value in models.py.
   Select an option: 1
   Please enter the default value as valid Python.
   The datetime and django.utils.timezone modules are available, so it is possible to provide e.g. timezone.now as a value.

   ''
   Invalid input: invalid character ''' (U+2018) (<string>, line 1)
   ''
   Migrations for 'myproject':
   myproject\migrations\0002_yingyongguanli_title_field22.py

    - Add field title_field22 to yingyongguanli

   (.venv) PS D:\python_workpace\django_xitong_shezhi\pythonProject\myproject> python manage.py migrate
   Operations to perform:
   Apply all migrations: admin, auth, contenttypes, myproject, sessions
   Running migrations:
   Applying myproject.0002_yingyongguanli_title_field22... OK
   (.venv) PS D:\python_workpace\django_xitong_shezhi\pythonProject\myproject> python manage.py runserver 10.0.4.144:8000
   Watching for file changes with StatReloader
   Performing system checks...

   System check identified no issues (0 silenced).
   August 07, 2024 - 15:05:12
   Django version 5.0.6, using settings 'myproject.settings'
   Starting development server at http://10.0.4.144:8000/
   Quit the server with CTRL-BREAK.