尝试将mySQL数据库迁移到Django项目时出现获取名称错误

Question

我有一个django-mySQL迁移问题。 我想不出是什么问题，如果你有什么想法请告诉我

我尝试将基本的sqlite3数据库更改为mySQL。我开始了一个新的django项目。我在mac上工作，我使用虚拟环境和python版本3.9.0。我已经安装了pip和自制软件。我用自制软件安装了mysql。我在mysql中创建了一个示例数据库，并在工作台中进行了检查。我开始使用mysql

我通过pip安装了mysqlclient（2.0.3）。 我打开了我的项目，并将settings.py中的数据库={…}更改为：

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'sample',
        'HOST': '127.0.0.1',
        'PORT': '3306',
        'USER': 'root',
        'PASSWORD': 'thisisreallymypassword',
    }
}

我的问题是，当我运行python manage.py-migrate命令时，我总是得到name错误：名称“\u mysql”没有定义。我通读了所有的话题，但没能找出问题所在。 有什么想法吗

(env) Csutkas-MacBookPro:greenium gezamacbookpro$ pip freeze
asgiref==3.3.1
Django==3.1.4
django-filter==2.4.0
django-mysql==3.10.0
mysqlclient==2.0.3
Pillow==8.0.1
pytz==2020.4
sqlparse==0.4.1
(env) Csutkas-MacBookPro:greenium gezamacbookpro$ python manage.py migrate
Traceback (most recent call last):
  File "/Users/gezamacbookpro/env/lib/python3.9/site-packages/MySQLdb/__init__.py", line 18, in <module>
    from . import _mysql
ImportError: dlopen(/Users/gezamacbookpro/env/lib/python3.9/site-packages/MySQLdb/_mysql.cpython-39-darwin.so, 2): Library not loaded: @rpath/libmysqlclient.21.dylib
  Referenced from: /Users/gezamacbookpro/env/lib/python3.9/site-packages/MySQLdb/_mysql.cpython-39-darwin.so
  Reason: image not found

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/gezamacbookpro/Developer/Django/greenium/manage.py", line 22, in <module>
    main()
  File "/Users/gezamacbookpro/Developer/Django/greenium/manage.py", line 18, in main
    execute_from_command_line(sys.argv)
  File "/Users/gezamacbookpro/env/lib/python3.9/site-packages/django/core/management/__init__.py", line 401, in execute_from_command_line
    utility.execute()
  File "/Users/gezamacbookpro/env/lib/python3.9/site-packages/django/core/management/__init__.py", line 377, in execute
    django.setup()
  File "/Users/gezamacbookpro/env/lib/python3.9/site-packages/django/__init__.py", line 24, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/Users/gezamacbookpro/env/lib/python3.9/site-packages/django/apps/registry.py", line 114, in populate
    app_config.import_models()
  File "/Users/gezamacbookpro/env/lib/python3.9/site-packages/django/apps/config.py", line 211, in import_models
    self.models_module = import_module(models_module_name)
  File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1030, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1007, in _find_and_load
  File "<frozen importlib._bootstrap>", line 986, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 680, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 790, in exec_module
  File "<frozen importlib._bootstrap>", line 228, in _call_with_frames_removed
  File "/Users/gezamacbookpro/env/lib/python3.9/site-packages/django/contrib/auth/models.py", line 2, in <module>
    from django.contrib.auth.base_user import AbstractBaseUser, BaseUserManager
  File "/Users/gezamacbookpro/env/lib/python3.9/site-packages/django/contrib/auth/base_user.py", line 48, in <module>
    class AbstractBaseUser(models.Model):
  File "/Users/gezamacbookpro/env/lib/python3.9/site-packages/django/db/models/base.py", line 122, in __new__
    new_class.add_to_class('_meta', Options(meta, app_label))
  File "/Users/gezamacbookpro/env/lib/python3.9/site-packages/django/db/models/base.py", line 326, in add_to_class
    value.contribute_to_class(cls, name)
  File "/Users/gezamacbookpro/env/lib/python3.9/site-packages/django/db/models/options.py", line 206, in contribute_to_class
    self.db_table = truncate_name(self.db_table, connection.ops.max_name_length())
  File "/Users/gezamacbookpro/env/lib/python3.9/site-packages/django/db/__init__.py", line 28, in __getattr__
    return getattr(connections[DEFAULT_DB_ALIAS], item)
  File "/Users/gezamacbookpro/env/lib/python3.9/site-packages/django/db/utils.py", line 214, in __getitem__
    backend = load_backend(db['ENGINE'])
  File "/Users/gezamacbookpro/env/lib/python3.9/site-packages/django/db/utils.py", line 111, in load_backend
    return import_module('%s.base' % backend_name)
  File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "/Users/gezamacbookpro/env/lib/python3.9/site-packages/django/db/backends/mysql/base.py", line 15, in <module>
    import MySQLdb as Database
  File "/Users/gezamacbookpro/env/lib/python3.9/site-packages/MySQLdb/__init__.py", line 24, in <module>
    version_info, _mysql.version_info, _mysql.__file__
NameError: name '_mysql' is not defined

Answer 1

我终于打通了。我所做的：

我从mac上完全卸载了mysql，然后： https://gist.github.com/vitorbritto/0555879fe4414d18569d

---

我不知道它是否与此相关，但我更新了brew并在清理时出错 brew清理：错误：权限被拒绝@apply2files

我根据这篇文章（https://github.com/Homebrew/homebrew-core/issues/45009）修正了这个问题：

sudo chown -R "$(whoami)":admin /usr/local/lib

---

然后我按照@cizario的建议（非常感谢）安装了mysql，方法如下： https://pypi.org/project/mysqlclient/

我使用了第一种方法，没有安装mysql客户端

# Assume you are activating Python 3 venv
$ brew install mysql
$ pip install mysqlclient

之后，我用brew启动了mysql服务：

brew services start mysql

我创建了一个新数据库：

mysql -u root
CREATE DATABASE sample;

然后我更新了django settings.py文件：

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

现在python manage.py migrate成功了

Answer 2

我也有类似的问题 “未加载库：@rpath/libmysqlclient.21.dylib” 在升级等，并尝试了很多很多东西在互联网上没有好的结果，但这最终为我工作改变了我的.zprofile 添加DYLD_库_路径

# Setting PATH for Python 3.9
# The original version is saved in .zprofile.pysave
PATH="/Library/Frameworks/Python.framework/Versions/3.9/bin:${PATH}"
export PATH
DYLD_LIBRARY_PATH="/usr/local/lib:${DYLD_LIBRARY_PATH}"
export DYLD_LIBRARY_PATH