# flask 数据库迁移报错（pymysql报错） flask项目中执行数据库迁移命令发生如下报错： ``` $ python manage.py db migrate Traceback (most recent call last): File "manage.py", line 25, in <module> manager.run() File "/home/ubuntu/anaconda3/envs/tf_gpu1.9/lib/python3.5/site-packages/flask_script/__init__.py", line 417, in run result = self.handle(argv[0], argv[1:]) File "/home/ubuntu/anaconda3/envs/tf_gpu1.9/lib/python3.5/site-packages/flask_script/__init__.py", line 386, in handle res = handle(*args, **config) File "/home/ubuntu/anaconda3/envs/tf_gpu1.9/lib/python3.5/site-packages/flask_script/commands.py", line 216, in __call__ return self.run(*args, **kwargs) File "/home/ubuntu/anaconda3/envs/tf_gpu1.9/lib/python3.5/site-packages/flask_migrate/__init__.py", line 96, in wrapped f(*args, **kwargs) File "/home/ubuntu/anaconda3/envs/tf_gpu1.9/lib/python3.5/site-packages/flask_migrate/__init__.py", line 212, in migrate version_path=version_path, rev_id=rev_id) File "/home/ubuntu/anaconda3/envs/tf_gpu1.9/lib/python3.5/site-packages/alembic/command.py", line 214, in revision script_directory.run_env() File "/home/ubuntu/anaconda3/envs/tf_gpu1.9/lib/python3.5/site-packages/alembic/script/base.py", line 489, in run_env util.load_python_file(self.dir, "env.py") File "/home/ubuntu/anaconda3/envs/tf_gpu1.9/lib/python3.5/site-packages/alembic/util/pyfiles.py", line 98, in load_python_file module = load_module_py(module_id, path) File "/home/ubuntu/anaconda3/envs/tf_gpu1.9/lib/python3.5/site-packages/alembic/util/compat.py", line 184, in load_module_py spec.loader.exec_module(module) File "<frozen importlib._bootstrap_external>", line 697, in exec_module File "<frozen importlib._bootstrap>", line 222, in _call_with_frames_removed File "migrations/env.py", line 25, in <module> str(current_app.extensions['migrate'].db.engine.url).replace('%', '%%')) File "/home/ubuntu/anaconda3/envs/tf_gpu1.9/lib/python3.5/site-packages/flask_sqlalchemy/__init__.py", line 998, in engine return self.get_engine() File "/home/ubuntu/anaconda3/envs/tf_gpu1.9/lib/python3.5/site-packages/flask_sqlalchemy/__init__.py", line 1017, in get_engine return connector.get_engine() File "/home/ubuntu/anaconda3/envs/tf_gpu1.9/lib/python3.5/site-packages/flask_sqlalchemy/__init__.py", line 594, in get_engine self._engine = rv = self._sa.create_engine(sa_url, options) File "/home/ubuntu/anaconda3/envs/tf_gpu1.9/lib/python3.5/site-packages/flask_sqlalchemy/__init__.py", line 1027, in create_engine return sqlalchemy.create_engine(sa_url, **engine_opts) File "/home/ubuntu/anaconda3/envs/tf_gpu1.9/lib/python3.5/site-packages/sqlalchemy/engine/__init__.py", line 525, in create_engine return strategy.create(*args, **kwargs) File "/home/ubuntu/anaconda3/envs/tf_gpu1.9/lib/python3.5/site-packages/sqlalchemy/engine/strategies.py", line 87, in create dbapi = dialect_cls.dbapi(**dbapi_args) File "/home/ubuntu/anaconda3/envs/tf_gpu1.9/lib/python3.5/site-packages/sqlalchemy/dialects/mysql/pymysql.py", line 62, in dbapi return __import__("pymysql") File "/home/ubuntu/anaconda3/envs/tf_gpu1.9/lib/python3.5/site-packages/pymysql/__init__.py", line 59, in <module> from . import connections # noqa: E402 File "/home/ubuntu/anaconda3/envs/tf_gpu1.9/lib/python3.5/site-packages/pymysql/connections.py", line 206 ): ^ SyntaxError: invalid syntax ``` 这是因为pymysql版本过高引起的报错，具体原因忘了，貌似是pymysql新版本不支持mysql 5.7版本数据库，使用```pip install```默认安装最新版本的pymysql，也就是1.0.0版本。 解决办法： 将pymysql降级到0.10.1 ``` pip install pymysql==0.10.1 ```