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)
    nickname = db.Column(db.String(20))
db.create_all()

user=User(username=‘1234‘,password=‘1234567890‘)
db.session.add(user)
db.session.commit()

user=User.query.filter(User.username==‘1234‘).first()
db.session.delete(user)
db.session.commit()

user=User.query.filter(User.username==‘1234‘).first()
user.username=‘1234‘
db.session.add(user)
db.session.commit()

user=User.query.filter(User.username==‘1234‘).first()
print(user.id,user.username,user.password)

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


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