ModuleNotFoundError：没有名为“MySQLdb”的模块 Amazon MySQL RDS SQLAlchemy

Question

我在将 Amazon AWS MySQL 与 SQLAlchemy 连接时遇到问题。按照提示，我已经连接了。

app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql://<user>:<password>@<host>/<dbname>

但有一个错误：

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/ec2-user/venv/lib/python3.7/site-packages/flask_sqlalchemy/__init__.py", line 514, in __get__
    return type.query_class(mapper, session=self.sa.session())
  File "/home/ec2-user/venv/lib/python3.7/site-packages/sqlalchemy/orm/scoping.py", line 74, in __call__
    return self.registry()
  File "/home/ec2-user/venv/lib/python3.7/site-packages/sqlalchemy/util/_collections.py", line 1001, in __call__
    return self.registry.setdefault(key, self.createfunc())
  File "/home/ec2-user/venv/lib/python3.7/site-packages/sqlalchemy/orm/session.py", line 2950, in __call__
    return self.class_(**local_kw)
  File "/home/ec2-user/venv/lib/python3.7/site-packages/flask_sqlalchemy/__init__.py", line 143, in __init__
    bind = options.pop('bind', None) or db.engine
  File "/home/ec2-user/venv/lib/python3.7/site-packages/flask_sqlalchemy/__init__.py", line 877, in engine
    return self.get_engine()
  File "/home/ec2-user/venv/lib/python3.7/site-packages/flask_sqlalchemy/__init__.py", line 896, in get_engine
    return connector.get_engine()
  File "/home/ec2-user/venv/lib/python3.7/site-packages/flask_sqlalchemy/__init__.py", line 559, in get_engine
    self._engine = rv = sqlalchemy.create_engine(info, **options)
  File "/home/ec2-user/venv/lib/python3.7/site-packages/sqlalchemy/engine/__init__.py", line 424, in create_engine
    return strategy.create(*args, **kwargs)
  File "/home/ec2-user/venv/lib/python3.7/site-packages/sqlalchemy/engine/strategies.py", line 81, in create
    dbapi = dialect_cls.dbapi(**dbapi_args)
  File "/home/ec2-user/venv/lib/python3.7/site-packages/sqlalchemy/dialects/mysql/mysqldb.py", line 102, in dbapi
    return __import__('MySQLdb')
ModuleNotFoundError: No module named 'MySQLdb'

我使用的是Python3.7版本。即使根据stackoverflow，我已经安装了pymysql，但仍然面临问题。

感谢你的回复。

Answer 1

如果您使用 PyMySQL 客户端连接到 MySQL，您的 SQLAlchemy 连接字符串需要以

 mysql+pymysql://

代替mysql://。

如果您连接，mysql://则需要安装 MySQLdb 库，如 Traceback 中所示。