Flask-SQLAlchemy

1.安装

pip install Flask-SQLAlchemy

起步

# 1. 创建表
from flask import Flask
from flask_sqlalchemy import SQLAlchemyapp = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql+pymysql://root:123@127.0.0.1/test?
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = Falsecharset=utf8'db = SQLAlchemy(app)class User(db.Model):id = db.Column(db.Integer,primary_key=True)username = db.Column(db.String(32),unique=True,nullable=True)db.create_all()
# 2. 添加数据
db.session.add(User(username='admin'))

加入组件

from flask import Flask# 导入Flask-SQLAlchemy中的SQLAlchemy
from flask_sqlalchemy import SQLAlchemy# 实例化SQLAlchemy
db = SQLAlchemy()
# PS : 实例化SQLAlchemy的代码必须要在引入蓝图之前from .views.users import userdef create_app():app = Flask(__name__)# 初始化App配置 这个app配置就厉害了,专门针对 SQLAlchemy 进行配置# SQLALCHEMY_DATABASE_URI 配置 SQLAlchemy 的链接字符串儿app.config["SQLALCHEMY_DATABASE_URI"] = "mysql+pymysql://root:DragonFire@127.0.0.1:3306/dragon?charset=utf8"# SQLALCHEMY_POOL_SIZE 配置 SQLAlchemy 的连接池大小app.config["SQLALCHEMY_POOL_SIZE"] = 5# SQLALCHEMY_POOL_TIMEOUT 配置 SQLAlchemy 的连接超时时间app.config["SQLALCHEMY_POOL_TIMEOUT"] = 15app.config["SQLALCHEMY_TRACK_MODIFICATIONS"] = False# 初始化SQLAlchemy , 本质就是将以上的配置读取出来db.init_app(app)app.register_blueprint(user)return app

2.创建表

from MyApp import dbBase = db.Model
# from sqlalchemy.ext.declarative import declarative_base
# Base = declarative_base()
# 每一次我们在创建数据表的时候都要做这样一件事
# 然而Flask-SQLAlchemy已经为我们把 Base 封装好了# 建立User数据表
class Users(Base): # Base实际上就是 db.Model__tablename__ = "users"__table_args__ = {"useexisting": True}# 在SQLAlchemy 中我们是导入了Column和数据类型 Integer 在这里# 就和db.Model一样,已经封装好了id = db.Column(db.Integer,primary_key=True)username = db.Column(db.String(32))password = db.Column(db.String(32))if __name__ == '__main__':from MyApp import create_appapp = create_app()# 这里你要回顾一下Flask应该上下文管理了# 离线脚本:with app.app_context():db.drop_all()db.create_all()

登录视图函数的应用

from flask import Blueprint, request, render_templateuser = Blueprint("user", __name__)from MyApp.models import Users
from MyApp import db@user.route("/login",methods=["POST","GET"])
def user_login():if request.method == "POST":username = request.form.get("username")password = request.form.get("password")# from sqlalchemy.orm import sessionmaker# Session = sessionmaker(engine)# db_sesson = Session()# 现在不用了,因为 Flask-SQLAlchemy 也已经为我们做好会话打开的工作db.session.add(Users(username=username,password=password))db.session.commit()# 然后再查询user_info = Users.query.filter(Users.username == username and User.password == password).first()print(user_info.username)if user_info:return f"登录成功{user_info.username}"return render_template("login.html")