flask SQLAlchemy 学习

官网：https://flask-sqlalchemy.palletsprojects.com

1.安装

pip install flask
pip install flask-sqlalchemy
pip install pymysql

1.设置连接数据URI
2.设置每次请求结束后自动提交数据库中的改动
	app.config['SQLALCHEMY_COMMIT_ON_TEARDOWW'] = False
	app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = True	#自动跟踪数据库
	app.config['SQLALCHEMY_ECHO'] = True

2.导入

from flask import Flask
from flask_sqlalchemy import SQLAlchemy

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql+pymysql://root:root@localhost/db_name'
db = SQLAlchemy(app)

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(80), unique=True, nullable=False)
    email = db.Column(db.String(120), unique=True, nullable=False)

    def __repr__(self):
        return '<User %r>' % self.username