Django 连接 Mysql (8.0.16) 失败

首先，确认数据库配置正确无误：

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',  # or use: mysql.connector.django
        'NAME': 'TestDB',
        'USER': 'Guest',
        'PASSWORD': 'admin',
        'HOST': '192.168.218.199',
        'PORT': '3306',
    }
}

但是启动项目时仍然出现如下错误：

System check identified no issues (0 silenced).
Exception in thread django-main-thread:
Traceback (most recent call last):
  File "G:\Projects\Python\WebTest\venv\lib\site-packages\django\db\backends\base\base.py", line 217, in ensure_connection
    self.connect()
  File "G:\Projects\Python\WebTest\venv\lib\site-packages\django\db\backends\base\base.py", line 195, in connect
    self.connection = self.get_new_connection(conn_params)
  File "G:\Projects\Python\WebTest\venv\lib\site-packages\django\db\backends\mysql\base.py", line 227, in get_new_connection
    return Database.connect(**conn_params)
  File "C:\Program Files (x86)\Python\Python37-32\lib\site-packages\MySQLdb\__init__.py", line 84, in Connect
    return Connection(*args, **kwargs)
  File "C:\Program Files (x86)\Python\Python37-32\lib\site-packages\MySQLdb\connections.py", line 164, in __init__
    super(Connection, self).__init__(*args, **kwargs2)
MySQLdb._exceptions.OperationalError: (2059, <NULL>)

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "C:\Program Files (x86)\Python\Python37-32\lib\threading.py", line 917, in _bootstrap_inner
    self.run()
  File "C:\Program Files (x86)\Python\Python37-32\lib\threading.py", line 865, in run
    self._target(*self._args, **self._kwargs)
  File "G:\Projects\Python\WebTest\venv\lib\site-packages\django\utils\autoreload.py", line 54, in wrapper
    fn(*args, **kwargs)
  File "G:\Projects\Python\WebTest\venv\lib\site-packages\django\core\management\commands\runserver.py", line 120, in inner_run
    self.check_migrations()
  File "G:\Projects\Python\WebTest\venv\lib\site-packages\django\core\management\base.py", line 453, in check_migrations
    executor = MigrationExecutor(connections[DEFAULT_DB_ALIAS])
  File "G:\Projects\Python\WebTest\venv\lib\site-packages\django\db\migrations\executor.py", line 18, in __init__
    self.loader = MigrationLoader(self.connection)
  File "G:\Projects\Python\WebTest\venv\lib\site-packages\django\db\migrations\loader.py", line 49, in __init__
    self.build_graph()
  File "G:\Projects\Python\WebTest\venv\lib\site-packages\django\db\migrations\loader.py", line 212, in build_graph
    self.applied_migrations = recorder.applied_migrations()
  File "G:\Projects\Python\WebTest\venv\lib\site-packages\django\db\migrations\recorder.py", line 73, in applied_migrations
    if self.has_table():
  File "G:\Projects\Python\WebTest\venv\lib\site-packages\django\db\migrations\recorder.py", line 56, in has_table
    return self.Migration._meta.db_table in self.connection.introspection.table_names(self.connection.cursor())
  File "G:\Projects\Python\WebTest\venv\lib\site-packages\django\db\backends\base\base.py", line 256, in cursor
    return self._cursor()
  File "G:\Projects\Python\WebTest\venv\lib\site-packages\django\db\backends\base\base.py", line 233, in _cursor
    self.ensure_connection()
  File "G:\Projects\Python\WebTest\venv\lib\site-packages\django\db\backends\base\base.py", line 217, in ensure_connection
    self.connect()
  File "G:\Projects\Python\WebTest\venv\lib\site-packages\django\db\utils.py", line 89, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "G:\Projects\Python\WebTest\venv\lib\site-packages\django\db\backends\base\base.py", line 217, in ensure_connection
    self.connect()
  File "G:\Projects\Python\WebTest\venv\lib\site-packages\django\db\backends\base\base.py", line 195, in connect
    self.connection = self.get_new_connection(conn_params)
  File "G:\Projects\Python\WebTest\venv\lib\site-packages\django\db\backends\mysql\base.py", line 227, in get_new_connection
    return Database.connect(**conn_params)
  File "C:\Program Files (x86)\Python\Python37-32\lib\site-packages\MySQLdb\__init__.py", line 84, in Connect
    return Connection(*args, **kwargs)
  File "C:\Program Files (x86)\Python\Python37-32\lib\site-packages\MySQLdb\connections.py", line 164, in __init__
    super(Connection, self).__init__(*args, **kwargs2)
django.db.utils.OperationalError: (2059, <NULL>)

原因：Django 对Mysql 8.0 版本的默认密码加密方式不支持

解决方法：修改密码加密方式。

首先做查询操作看一下plugin：

use mysql;
select user,plugin from user;

结果如下：

Mysql 官方原文：

In MySQL 8.0, caching_sha2_password is the default authentication plugin rather than mysql_native_password.

链接：https://dev.mysql.com/doc/refman/8.0/en/sha256-pluggable-authentication.html

但是Django对caching_sha2_password不支持

所以我们下一步就是对其进行修改：

alter user 'Guest'@'%' identified with mysql_native_password by 'admin';

此时已经修改成功，我们再次查询看一下结果：

重新开启Django项目已经可以正常连接。