调试代码出现错误from app import db

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PyDev console: starting.
% i; _# o' \! ePython 3.8.8 (tags/v3.8.8:024d805, Feb 19 2021, 13:18:16) [MSC v.1928 64 bit (AMD64)] on win32
; V8 A/ E6 N. X+ ~8 Rfrom app import db
Traceback (most recent call last):
  File "<input>", line 1, in <module>
  File "C:\Program Files\JetBrains\PyCharm Community Edition 2020.1.5\plugins\python-ce\helpers\pydev\_pydev_bundle\pydev_import_hook.py", line 21, in do_import
2 Q$ Y. |2 w  g+ |4 {' P& f    module = self._system_import(name, *args, **kwargs)
ModuleNotFoundError: No module named 'app'

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& u1 h( g( L: }, }这里需要安装下app

pip install app即可：解决问题。

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from app import db
Traceback (most recent call last):
  File "<input>", line 1, in <module>
ImportError: cannot import name 'db' from 'app' (C:\Users\xxxxx\testflask\venv\lib\site-packages\app\__init__.py)
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Traceback (most recent call last):
  File "<input>", line 1, in <module>
ImportError: cannot import name 'db' from 'app' (C:\Users\xxxxx\pythonProject\venv\lib\site-packages\app\__init__.py)

& ~6 l3 J+ j2 Y& X; d
$ e+ k2 N3 f3 n" V遇到问题，我一直没有想过问题在哪里，为什么引入不了这个db
& `% c7 }  |0 l. A在python console上执行时一直报错，但视频里却能正常，为什么？
/ q# X+ j8 F, [7 T4 [>>>from app import db
' k5 m8 Z- k( S  FTraceback (most recent call last):
% K% v3 y( p- _, _  File "<input>", line 1, in <module>
ImportError: cannot import name 'db' from 'app' (C:\Users\xxxxx\pythonProject\pythonProject\venv\lib\site-packages\app\__init__.py)

% L7 t, |( J4 e2 {8 d( W% z# A解决问题原因：
7 t$ |& v3 Z- X: X! X2 }% ^一次偶然的问题，一直测试，发现一个问题。我们的xxxx.py 这个flask文件的问题。
我们取名叫什么，就用前面的名称  比如app.py就用app  完整的输入就是from app import db
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但我这里的文件名称是appflask.py  那么我们这边就要在执行的时候，输入from appflask import db

>>>from appflask import db
C:\Users\xxxxx\venv\lib\site-packages\flask_sqlalchemy\__init__.py:834: FSADeprecationWarning: SQLALCHEMY_TRACK_MODIFICATIONS adds significant overhead and will be disabled by default in the future.  Set it to True or False to suppress this warning.
  warnings.warn(FSADeprecationWarning(

9 g) K% ~( y+ \& l' V& u即可执行后面的db.create_all()等命令了。