错误信息：

Traceback (most recent call last):
  File "D:\MyProject\bookmanager02\manage.py", line 22, in <module>
    main()
  File "D:\MyProject\bookmanager02\manage.py", line 18, in main
    execute_from_command_line(sys.argv)
  File "D:\下载\PYTHON\Lib\site-packages\django\core\management\__init__.py", line 442, in execute_from_command_line
    utility.execute()
  File "D:\下载\PYTHON\Lib\site-packages\django\core\management\__init__.py", line 416, in execute
    django.setup()
  File "D:\下载\PYTHON\Lib\site-packages\django\__init__.py", line 24, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "D:\下载\PYTHON\Lib\site-packages\django\apps\registry.py", line 116, in populate
    app_config.import_models()
  File "D:\下载\PYTHON\Lib\site-packages\django\apps\config.py", line 269, in import_models
    self.models_module = import_module(models_module_name)
                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "D:\下载\PYTHON\Lib\importlib\__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1206, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1178, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1149, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 690, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 940, in exec_module
  File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
  File "D:\下载\PYTHON\Lib\site-packages\django\contrib\auth\models.py", line 3, in <module>
    from django.contrib.auth.base_user import AbstractBaseUser, BaseUserManager
  File "D:\下载\PYTHON\Lib\site-packages\django\contrib\auth\base_user.py", line 57, in <module>
    class AbstractBaseUser(models.Model):
  File "D:\下载\PYTHON\Lib\site-packages\django\db\models\base.py", line 143, in __new__
    new_class.add_to_class("_meta", Options(meta, app_label))
  File "D:\下载\PYTHON\Lib\site-packages\django\db\models\base.py", line 371, in add_to_class
    value.contribute_to_class(cls, name)
  File "D:\下载\PYTHON\Lib\site-packages\django\db\models\options.py", line 243, in contribute_to_class
    self.db_table, connection.ops.max_name_length()
                   ^^^^^^^^^^^^^^
  File "D:\下载\PYTHON\Lib\site-packages\django\utils\connection.py", line 15, in __getattr__
    return getattr(self._connections[self._alias], item)
                   ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^
  File "D:\下载\PYTHON\Lib\site-packages\django\utils\connection.py", line 62, in __getitem__
    conn = self.create_connection(alias)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "D:\下载\PYTHON\Lib\site-packages\django\db\utils.py", line 193, in create_connection
    backend = load_backend(db["ENGINE"])
              ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "D:\下载\PYTHON\Lib\site-packages\django\db\utils.py", line 113, in load_backend
    return import_module("%s.base" % backend_name)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "D:\下载\PYTHON\Lib\importlib\__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "D:\下载\PYTHON\Lib\site-packages\django\db\backends\mysql\base.py", line 35, in <module>
    raise ImproperlyConfigured(
django.core.exceptions.ImproperlyConfigured: mysqlclient 1.4.3 or newer is required; you have 1.0.3.

解决： 

 1，尝试下载并更新mysqlclient

pip install mysqlclient 

 

2，如果还是报错：

  File "D:\下载\PYTHON\Lib\site-packages\django\db\backends\mysql\base.py", line 35, in <module>
    raise ImproperlyConfigured(
django.core.exceptions.ImproperlyConfigured: mysqlclient 1.4.3 or newer is required; you have 1.0.3.

     进入 File "D:\下载\PYTHON\Lib\site-packages\django\db\backends\mysql\base.py", line 35, in <module>这个目录

   version = Database.version_info
if version < (1, 4, 3):
  raise ImproperlyConfigured(
        "mysqlclient 1.4.3 or newer is required; you have %s." % Database.__version__
    )

 找到这段代码把if后面注释掉

注释掉后：

version = Database.version_info
#if version < (1, 4, 3):
 #   raise ImproperlyConfigured(
  #      "mysqlclient 1.4.3 or newer is required; you have %s." % Database.__version__
   # )

 

 再进行数据迁移，

PS D:\MyProject\bookmanager02> python manage.py makemigrations
Migrations for 'book':
  book\migrations\0001_initial.py
    - Create model BookInfo

 迁移成功！