我在 vsc 和 Windows 10 中的 Flask 中創建數據庫時遇到問題。有人可以幫助解決這個問題嗎？

Question

我需要創建數據庫。

這是我需要鍵入以創建數據庫的內容。

from flaskblog import db
from flaskblog.models import User, Post, etc  
db.create_all()

我首先在 Visual Studio 代碼中將python輸入到 powershell 中。

然后我輸入from flaskblog import db並得到錯誤

導入錯誤：無法從 'flaskblog' 導入名稱 'db' (C:\\Users\\n\\OneDrive\\Desktop\\codingfiles2use\\flaskblog_ init _.py)

這是我的文件樹。 文件樹

我該如何解決？ 謝謝

應用程序

from flask import Flask  
# make SQLAlchemy work 
from flask_sqlalchemy import SQLAlchemy
# make login work
from flask_login import LoginManager# user_loaded_from_header
# make crf protection work 
from flask_wtf.csrf import CSRFProtect





# setup databases
db = SQLAlchemy()
# Make Login user variable work ?
login_manager = LoginManager()
# Setup CSRF protection. This allows html forms to work and be secure.  
csrf = CSRFProtect()


# imports config from config.py
from flaskblog.config import Config


def create_app(config_class=Config): 
    app = Flask(__name__) 
    app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False 
    # what does this do?
    app.config.from_object(config_class)
    
    db.init_app(app)
    login_manager.init_app(app)
    csrf.init_app(app)
    
    from flaskblog.usersinfo.routes import usersinfo
    # why lowercse b in blueprints ?
    app.register_blueprint(usersinfo)
    return app 

from .models import User 

@login_manager.user_loader
def load_user(user_id):
    return User.get_by_id(user_id)

運行文件

from flaskblog.app import create_app
app = create_app()
if __name__ == '__main__': 
    app.run(debug=True)

配置文件

import os     

class Config:
    # Setup CSRF secret key
    SECRET_KEY = os.urandom(32)
    SQLALCHEMY_DATABASE_URI = 'sqlite:///tmp/test.db'

當我打字時

from flaskblog import db
from flaskblog.models import User   
db.create_all()

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Users\nmyle\AppData\Local\Programs\Python\Python39\lib\site-packages\flask_sqlalchemy\__init__.py", line 1094, in create_all
    self._execute_for_all_tables(app, bind, 'create_all')
  File "C:\Users\nmyle\AppData\Local\Programs\Python\Python39\lib\site-packages\flask_sqlalchemy\__init__.py", line 1071, in _execute_for_all_tables   
    app = self.get_app(app)
  File "C:\Users\nmyle\AppData\Local\Programs\Python\Python39\lib\site-packages\flask_sqlalchemy\__init__.py", line 1042, in get_app
    raise RuntimeError(
RuntimeError: No application found. Either work inside a view function or push an application context. See http://flask-sqlalchemy.pocoo.org/contexts/.

我嘗試通過添加不同的代碼塊之一來完成代碼，但它不起作用我仍然收到錯誤。 我嘗試了所有代碼塊我該如何解決這個問題？

http://flask-sqlalchemy.pocoo.org/contexts/ 。

Answer 1

您需要使用 app_context

在終端中運行所有這些命令

from flaskblog.app import db,create_app
from flaskblog.models import User  
app = create_app()
with app.app_context():
    db.create_all()