关于#Flask#的问题，如何解决？(语言-python)

Question

Flask连接MySQL数据库时报错RuntimeError: Working outside of application context.
源码:

from flask_sqlalchemy import SQLAlchemy
import pymysql
app = Flask(__name__)

db = SQLAlchemy(app)

class Users(db.Model):
    __tablename__ = 'users'
    id = db.Column(db.Integer,primary_key = True)
    username = db.Column(db.String(80),nullable = False)
    age = db.Column(db.Integer)
    email = db.Column(db.String(120),unique = True)

    def __init__(self,username,age,email):
         self.username = username
         self.age = age
         self.email = email
         with app.app_context():
             return
    def __repr__(self):
         return '<User:%r>' % self.username

db.create_all()
if __name__ == '__main__':
    app.run(debug=True)

Answer 1

只要在最后加上

 with app.app_context():
        db.create_all()

就可以了

from flask_sqlalchemy import SQLAlchemy
import pymysql
app = Flask(__name__)

db = SQLAlchemy(app)

class Users(db.Model):
    __tablename__ = 'users'
    id = db.Column(db.Integer,primary_key = True)
    username = db.Column(db.String(80),nullable = False)
    age = db.Column(db.Integer)
    email = db.Column(db.String(120),unique = True)

    def __init__(self,username,age,email):
         self.username = username
         self.age = age
         self.email = email
         with app.app_context():
             return
    def __repr__(self):
         return '<User:%r>' % self.username

db.create_all()
if __name__ == '__main__':
    app.run(debug=True)
    with app.app_context():
        db.create_all()