如何解决Django切换MySQL时的NameError: name '_mysql' is not defined错误

问题场景 #

启动Django项目后，原使用SQLite3创建模型和迁移文件，现切换至MySQL+Workbench开发。完成MySQL、mysqlclient、Workbench安装，并在settings.py配置数据库信息后，执行python manage.py migrate或python manage.py runserver触发错误。

数据库配置（settings.py） #

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'storedb',
        'USER': 'root',
        'PASSWORD': '2E71Blue.8',
        'PORT': 3306,
        'HOST': '127.0.0.1',
    }
}

错误回溯信息 #

Watching for file changes with StatReloader
Exception in thread django-main-thread:
Traceback (most recent call last):
  File "/Users/cecibenitez/.local/share/virtualenvs/storebackend-1ILPqCOa/lib/python3.10/site-packages/MySQLdb/__init__.py", line 18, in <module>
    from . import _mysql
ImportError: dlopen(/Users/cecibenitez/.local/share/virtualenvs/storebackend-1ILPqCOa/lib/python3.10/site-packages/MySQLdb/_mysql.cpython-310-darwin.so, 2): Symbol not found: _mysql_affected_rows
  Referenced from: /Users/cecibenitez/.local/share/virtualenvs/storebackend-1ILPqCOa/lib/python3.10/site-packages/MySQLdb/_mysql.cpython-310-darwin.so
  Expected in: flat namespace
 in /Users/cecibenitez/.local/share/virtualenvs/storebackend-1ILPqCOa/lib/python3.10/site-packages/MySQLdb/_mysql.cpython-310-darwin.so

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/threading.py", line 1016, in _bootstrap_inner
    self.run()
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/threading.py", line 953, in run
    self._target(*self._args, **self._kwargs)
  File "/Users/cecibenitez/.local/share/virtualenvs/storebackend-1ILPqCOa/lib/python3.10/site-packages/django/utils/autoreload.py", line 64, in wrapper
    fn(*args, **kwargs)
  File "/Users/cecibenitez/.local/share/virtualenvs/storebackend-1ILPqCOa/lib/python3.10/site-packages/django/core/management/commands/runserver.py", line 125, in inner_run
    autoreload.raise_last_exception()
  File "/Users/cecibenitez/.local/share/virtualenvs/storebackend-1ILPqCOa/lib/python3.10/site-packages/django/utils/autoreload.py", line 87, in raise_last_exception
    raise _exception[1]
  File "/Users/cecibenitez/.local/share/virtualenvs/storebackend-1ILPqCOa/lib/python3.10/site-packages/django/core/management/__init__.py", line 394, in execute
    autoreload.check_errors(django.setup)()
  File "/Users/cecibenitez/.local/share/virtualenvs/storebackend-1ILPqCOa/lib/python3.10/site-packages/django/utils/autoreload.py", line 64, in wrapper
    fn(*args, **kwargs)
  File "/Users/cecibenitez/.local/share/virtualenvs/storebackend-1ILPqCOa/lib/python3.10/site-packages/django/__init__.py", line 24, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/Users/cecibenitez/.local/share/virtualenvs/storebackend-1ILPqCOa/lib/python3.10/site-packages/django/apps/registry.py", line 116, in populate
    app_config.import_models()
  File "/Users/cecibenitez/.local/share/virtualenvs/storebackend-1ILPqCOa/lib/python3.10/site-packages/django/apps/config.py", line 269, in import_models
    self.models_module = import_module(models_module_name)
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1050, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 688, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 883, in exec_module
  File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
  File "/Users/cecibenitez/.local/share/virtualenvs/storebackend-1ILPqCOa/lib/python3.10/site-packages/django/contrib/auth/models.py", line 3, in <module>
    from django.contrib.auth.base_user import AbstractBaseUser, BaseUserManager
  File "/Users/cecibenitez/.local/share/virtualenvs/storebackend-1ILPqCOa/lib/python3.10/site-packages/django/contrib/auth/base_user.py", line 57, in <module>
    class AbstractBaseUser(models.Model):
  File "/Users/cecibenitez/.local/share/virtualenvs/storebackend-1ILPqCOa/lib/python3.10/site-packages/django/db/models/base.py", line 143, in __new__
    new_class.add_to_class("_meta", Options(meta, app_label))
  File "/Users/cecibenitez/.local/share/virtualenvs/storebackend-1ILPqCOa/lib/python3.10/site-packages/django/db/models/base.py", line 371, in add_to_class
    value.contribute_to_class(cls, name)
  File "/Users/cecibenitez/.local/share/virtualenvs/storebackend-1ILPqCOa/lib/python3.10/site-packages/django/db/models/options.py", line 243, in contribute_to_class
    self.db_table, connection.ops.max_name_length()
  File "/Users/cecibenitez/.local/share/virtualenvs/storebackend-1ILPqCOa/lib/python3.10/site-packages/django/utils/connection.py", line 15, in __getattr__
    return getattr(self._connections[self._alias], item)
  File "/Users/cecibenitez/.local/share/virtualenvs/storebackend-1ILPqCOa/lib/python3.10/site-packages/django/utils/connection.py", line 62, in __getitem__
    conn = self.create_connection(alias)
  File "/Users/cecibenitez/.local/share/virtualenvs/storebackend-1ILPqCOa/lib/python3.10/site-packages/django/db/utils.py", line 193, in create_connection
    backend = load_backend(db["ENGINE"])
  File "/Users/cecibenitez/.local/share/virtualenvs/storebackend-1ILPqCOa/lib/python3.10/site-packages/django/db/utils.py", line 113, in load_backend
    return import_module("%s.base" % backend_name)
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "/Users/cecibenitez/.local/share/virtualenvs/storebackend-1ILPqCOa/lib/python3.10/site-packages/django/db/backends/mysql/base.py", line 15, in <module>
    import MySQLdb as Database
  File "/Users/cecibenitez/.local/share/virtualenvs/storebackend-1ILPqCOa/lib/python3.10/site-packages/MySQLdb/__init__.py", line 24, in <module>
    version_info, _mysql.version_info, _mysql.__file__
NameError: name '_mysql' is not defined

已尝试方法 #

• 安装mysqlclient依赖的C包
• 配置.zprofile中的MySQL路径
• 升级MySQL至8.0.33版本

当前环境信息 #

• Python版本：3.10.5
• MySQL版本：Ver 8.0.33 for macos11.7 on x86_64 (Homebrew)

Pipfile内容 #

[[source]]
url = "https://pypi.org/simple"
verify_ssl = true
name = "pypi"

[packages]
django = "*"
django-debug-toolbar = "*"
mysqlclient = "*"
pymysql = "*"

[dev-packages]

[requires]
python_version = "3.10"

解决方案 #

方案1：用pymysql替代mysqlclient #

已安装pymysql，直接让Django适配：

1. 在项目根目录的__init__.py中添加代码：

import pymysql
pymysql.install_as_MySQLdb()

2. 重新执行python manage.py migrate或runserver

方案2：重新编译mysqlclient适配本地MySQL #

确保mysqlclient基于当前MySQL环境编译：

1. 卸载现有mysqlclient：

pip uninstall mysqlclient -y

2. 指定Homebrew安装的MySQL路径，重新编译安装：

export PATH="/usr/local/mysql/bin:$PATH"
export LDFLAGS="-L/usr/local/mysql/lib"
export CPPFLAGS="-I/usr/local/mysql/include"
pip install mysqlclient --no-binary mysqlclient

3. 激活虚拟环境后重新运行命令

方案3：检查架构兼容性 #

macOS下Python与MySQL架构不匹配（如x86_64 vs arm64）会导致符号缺失：

• 检查Python架构：python -c "import platform; print(platform.architecture())"
• 检查MySQL架构：mysql -V（查看输出中的x86_64或arm64）
  若不一致，重新安装对应架构的Python或MySQL

内容的提问来源于stack exchange，提问作者CeciResponde