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=TabError,autoincrement=True)
    username=db.Column(db.String(20),nullable=False)
    password=db.Column(db.String(20),nullable=False)

#数据添加
user=User(username='ma',password='gg')
db.session.add(user)
db.session.commit()
db.create_all()

#数据更新

user = User.query.filter(User.username=='hh').first()
user.password='gg'
db.session.commit()


# 数据查询
user = User.query.filter(User.username=='ma').first()
print(user.username,user.password)

# 数据删除
user = User.query.filter(User.username=='ma').first()
db.session.delete(user)
db.session.commit()




@app.route('/')
def hello_world():
    return 'hello World'


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