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))
    # db.create_all()
    #增
    user = User(username='xyjie', password='xyj19950326')
    db.session.add(user)
    db.session.commit()
    # 删
    user = User.query.filter(User.username == 'xyjie2').first()
    user.password = 'xyj19950326'
    db.session.delete(user)
    db.session.commit()
    # 改
    user = User.query.filter(User.username == 'xyjie8').first()
    user.username = 'xyjie10'
    db.session.add(user)
    db.session.commit()
    # 查
    user = User.query.filter(User.username == 'xyjie8').first()
    print(user.id, user.username, user.password)

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

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

#增

#删

#查

#改