demo.py(数据库的修改、删除):
from flask import Flask, current_app
from flask_sqlalchemy import SQLAlchemy # 导入
from demo1 import User # 导入模型类
# 创建数据库sqlalchemy工具对象
db = SQLAlchemy(current_app)
# 修改
user1 = User.query.get(1)
user1.name = "zhang2" # 修改
db.session.commit() # 提交
# 通过update()修改
count = User.query.filter_by(name='zhang').update({'name':'li', 'age':18}) # 返回受影响行数
db.session.commit() # 提交
# 删除
user2 = User.query.get(1)
db.session.delete(user2)
db.session.commit()