通过用户模型，对数据库进行增删改查操作。

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

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

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

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

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),nullable=False)
    #   db.create_all()
    
# 增加
user = User(username='mis1114',password = 'mis1114')
db.session.add(user)
db.session.commit()

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

# 删除
user =User.query.filter(User.username =='mis1114').first()
print(user.username,user.password)
db.session.delete(user)
db.session.commit()

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



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


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