通过用户模型，对数据库进行增删改查操作。

from flask import Flask
from flask_sqlalchemy import SQLAlchemy
import config

app = Flask(__name__)
app.config.from_object(config)

db = SQLAlchemy(app)

class User(db.Model):
    __tablename__ = ‘user‘
    id = db.Column(db.Integer,primary_key=True,autoincrement=True)
    username = db.Column(db.String(20),nullable=False)
    password = db.Column(db.String(20),nullable=False)

#db.create_all()

user=User(username=‘yyyy1‘,password=‘111111‘)
db.session.add(user)
db.session.commit()

user = User.query.filter(User.username == ‘yyyy1‘).first()


user=User.query.filter(User.username==‘yyyy1‘).first()
user.password=‘234567‘
print(user.username,user.password)
db.session.commit()

user=User.query.filter(User.username == ‘yyyy1‘).first()
db.session.delete(user)
db.session.commit()

@app.route(‘/‘)
def hello_world():
    return ‘Hello World!‘


if __name__ == ‘__main__‘:
    app.run()