从__init__.py导入时出现Python导入错误

Question

我在名为users的软件包中包含以下文件：

文件__init__.py：

from flask_sqlalchemy import SQLAlchemy
from .views import UserDetails, UserList

db = SQLAlchemy()

文件models.py：

from users import db

class User(db.Model):
    pass

和文件views.py：

from .models import User
from users import db

#code

但是发生了以下导入异常：

Error: While importing "users", an ImportError was raised:

Traceback (most recent call last):
  File "/var/www/microservices/venv/lib/python3.6/site-packages/flask/cli.py", line 240, in locate_app
    __import__(module_name)
  File "/var/www/microservices/Flask_Microservices/users/__init__.py", line 9, in <module>
    from .views import UserDetails, UserList
  File "/var/www/microservices/Flask_Microservices/users/views.py", line 5, in <module>
    from .models import User
  File "/var/www/microservices/Flask_Microservices/users/models.py", line 2, in <module>
    from users import db
ImportError: cannot import name 'db'

关于我的进口商品有什么问题的任何想法吗？

Answer 1

疯狂的猜测。尝试移动

from .views import UserDetails, UserList

在db = SQLAlchemy()下，看起来像

from flask_sqlalchemy import SQLAlchemy

db = SQLAlchemy()

from .views import UserDetails, UserList

从视图执行导入时，它会尝试从views.py文件中的 init .py导入数据库。它尚不存在，因此会发生错误。至少我是这样认为的。