Importerror：无法在flask中导入名称db

我目前正在尝试使用SQLAlchemy获取注册并使用Flask登录数据库方面。当我运行app.py文件时，我收到错误：



ImportError：无法在Flask中导入名称db



我对python flask很新，似乎无法解决这个问题。提前感谢您的建议。



我尝试过：



app.py文件

Im currently trying to get a register and login working with Flask using SQLAlchemy for the database side of things. When I run the app.py file I get the error:

ImportError: cannot import name db in Flask

I'm fairly new to python flask and can't seem to figure this out. Thank you in advance for the suggestions.

What I have tried:

app.py File

from flask import Flask, request, render_template, redirect, url_for
from forms import SignupForm

from models import db
def init_db():
    db.init_app(app)
    db.app = app
    db.create_all()

from flask_login import LoginManager, login_user, login_required, logout_user 
login_manager = LoginManager()
login_manager.init_app(app)

app = Flask(__name__)
app.secret_key = 'secretkeyhereplease'
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:////database/database.sqlite'

@app.route('/')
def index():
    return "Welcome to Flask"

@app.route('/signup', methods=['GET', 'POST'])
def signup():
    form = SignupForm()

    if request.method == 'GET':
        return render_template('signup.html', form = form)
    elif request.method == 'POST':
        if form.validate_on_submit():
            if user.query.filter_by(email=form.email.data).first():
                return "Email address already exists"
            else:
                newuser = User(form.email.data, form.password.data)
                db.session.add(newuser)
                db.session.commit()

                login_user(newuser)

                return "Will create user here"
        else: 
            return "Form didn't validate"

@login_manager.user_loader
def load_user(email):
    return User.query.filter_by(email = email).first()

@app.route('/protected')
@login_required
def protected():
    return "protected area"

app.route('/login', methods=['GET', 'POST'])
def login():
    form = SignupForm()

    if request.method == 'GET':
        return render_template('login.html', form=form)
    elif request.method == 'POST':
        if form.validate_on_submit():
            user=User.query.filter_by(email=form.email.data).first()
            if user:
                if usee.password == form.password.data:
                    login_user(user)
                    return "User logged in"
                else:
                    return "Wrong password"
            else:
                return "User doesn't exist"
    else:
            return "Form not validated"     

if __name__ == '__main__':
    app.init_db()
        app.run('0.0.0.0', debug=True)

models.py文件

models.py File

from app import app
from flask_sqlalchemy import SQLAlchemy
db = SQLAlchemy(app)

class User(db.Model):
    email = db.Column(db.String(80), primary_key=True, unique=True)
    password = db.Column(db.String(80))

    def __init__(self, email, password):
        self.email = email
        self.password = password

    def __repr__(self):
        return '<User %r>' % self.email

    def is_authenticated(self):
        return True
    def is_active(self):
        return True
    def is_anonymous(self):
        return False
    def get_id(self):
        return str(self.email)