# -*- coding: utf-8 -*-from sqlalchemy import create_engine, Column, String, Integer, ForeignKey, Table,Textfrom sqlalchemy.ext.declarative import declarative_basefrom sqlalchemy.orm import sessionmaker, relationshipDB_URI = "mysql+pymysql://root:root@127.0.0.1:3306/xiachufang2"engine = create_engine(DB_URI)Base = declarative_base(engine)session = sessionmaker(engine)()class Recipe_Mat(Base): __tablename__ = ‘recipe_mat‘ material_id = Column(Integer, ForeignKey(‘material.id‘),primary_key=True) food_id = Column(Integer, ForeignKey(‘food.id‘),primary_key=True)class Recipe(Base): __tablename__=‘food‘ id=Column(Integer,autoincrement=True,primary_key=True) food=Column(String(128),nullable=False) step=Column(Text) tip=Column(Text) description=Column(Text) materials=relationship(‘Material‘,secondary=‘recipe_mat‘)class Material(Base): __tablename__ = ‘material‘ id = Column(Integer, autoincrement=True, primary_key=True) material = Column(String(128), nullable=False) volume=Column(String(128)) foods = relationship(‘Recipe‘, secondary=‘recipe_mat‘)