在我的 Flask 应用程序中遇到运行时错误

Question

我在 Flask 应用程序中遇到运行时错误，我正在寻求帮助来解决该问题。我的 Python 文件名为“auth.py”，附近有一个“database.db”文件。

这是我面临的错误消息：

File "<stdin>", line 1, in <module>
File "path\to\auth.py", line 10, in <module>
db = SQLAlchemy(app)
...
RuntimeError: Either 'SQLALCHEMY_DATABASE_URI' or 'SQLALCHEMY_BINDS' must be set.

from flask import Flask, render_template, url_for, redirect
from flask_sqlalchemy import SQLAlchemy
from flask_login import UserMixin, login_user, LoginManager, login_required, logout_user, current_user
from flask_wtf import FlaskForm
from wtforms import StringField, PasswordField, SubmitField
from wtforms.validators import InputRequired, Length, ValidationError
from flask_bcrypt import Bcrypt

app = Flask(__name__)
db = SQLAlchemy(app)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///database.db'
app.config['SECRET_KEY'] = 'thisisasecretkey'


class User(db.Model, UserMixin):
    id = db.Column(db.Integer, primary_key=True)    
    username = db.Column(db.String(20), nullable=False, unique=True)
    password = db.Column(db.String(80), nullable=False)



@app.route('/')
def home():
    return render_template('base.html')


@app.route('/login', methods=['GET', 'POST'])
def login():
    return render_template('login.html')



@ app.route('/register', methods=['GET', 'POST'])
def register():
    return render_template('register.html')


if __name__ == "__main__":
    app.run(debug=True)

我已确认“database.db”文件与“auth.py”位于同一目录中。是什么导致了这个运行时错误，我该如何解决它？

任何帮助或指导将不胜感激。

谢谢！

Answer 1

你应该添加

app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///database.db'
app.config['SECRET_KEY'] = 'thisisasecretkey'

在

db = SQLAlchemy(app)

之前。

Answer 2

在设置 DB_PARAMS（例如

SQLALCHEMY_DATABASE_URI

）之前，不应启动数据库。这是因为

SQLAlchemy(app)

加载了所有配置变量。

在您的情况下，您正在初始化

db = SQLAlchemy(app)

，它尝试加载

SQLALCHEMY_DATABASE_URI

（尚未设置），因此您会看到错误。

更新代码：

from flask import Flask, render_template, url_for, redirect
from flask_sqlalchemy import SQLAlchemy
from flask_login import UserMixin, login_user, LoginManager, login_required, logout_user, current_user
from flask_wtf import FlaskForm
from wtforms import StringField, PasswordField, SubmitField
from wtforms.validators import InputRequired, Length, ValidationError
from flask_bcrypt import Bcrypt

app = Flask(__name__)

app.config['SECRET_KEY'] = 'thisisasecretkey' # also move secret key to top. 
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///database.db'

# move here
db = SQLAlchemy(app)


class User(db.Model, UserMixin):
    id = db.Column(db.Integer, primary_key=True)    
    username = db.Column(db.String(20), nullable=False, unique=True)
    password = db.Column(db.String(80), nullable=False)



@app.route('/')
def home():
    return render_template('base.html')


@app.route('/login', methods=['GET', 'POST'])
def login():
    return render_template('login.html')



@ app.route('/register', methods=['GET', 'POST'])
def register():
    return render_template('register.html')


if __name__ == "__main__":
    app.run(debug=True)