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()

py:

from flask import Flask, render_template
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=TabError,autoincrement=True)
    username = db.Column(db.String(20), nullable=False)
    password = db.Column(db.String(20), nullable=False)
#增
user = User(username ='mis1234',password='111111' )
db.session.add(user)
db.session.commit()
#查
user=User.query.filter(User.username =='mis1234').first()
print(user.username,user.password)
#删
user=User.query.filter(User.username =='liangshu').first()
db.session.delete(user)
db.session.commit()
#改
user=User.query.filter(User.username =='mis1114').first()
user.password='mis1114'
db.session.commit()
@app.route('/')
def base():
    return render_template('base.html')


@app.route('/login/')
def login():
    return render_template('login.html')


@app.route('/regist/')
def regist():
    return render_template('register.html')

@app.route('/label/')
def label():
    return render_template('label.html')
if __name__ == '__main__':
    app.run(debug=True)

SQLALCHEMY_DATABASE_URI='mysql+pymysql://root:@127.0.0.1:3306/mis_db?charset=utf8'
SQLALCHEMY_TRACK_MODIFICATIONS = False