作业24-通过用户模型，对数据库进行增删改查操作

增加：
db.session.add(user)
db.session.commit()

user = User(username = 'mis1114',password = 'hehe111')
db.session.add(user)
db.session.commit()

 

 查询：
User.query.filter(User.username == 'mis1114').first()

user = User.query.filter(User.username == 'mis1114').first()
user.password = 'hehe111'
db.session.commit()

 

修改：
user.password = '111111'
db.session.commit()

user = User.query.filter(User.username == 'mis1114').first()
user.password = '111111'
db.session.commit()

 

 删除：
db.session.delete(user)
db.session.commit()

user = User.query.filter(User.username == 'mis1114').first()
db.session.delete(user)
db.session.commit()