Python3-sqlalchemy-orm 联表查询-无外键关系

Posted 2021-02-01 裸奔的小鸵鸟

 

 

#-*-coding:utf-8-*-
#__author__ = "logan.xu"


import sqlalchemy
from sqlalchemy import create_engine,func
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column,Integer,String,DATE
from sqlalchemy.orm import sessionmaker

engine=create_engine("mysql+pymysql://root:12345678@localhost/news",encoding=\'utf-8\',echo=True)
Base=declarative_base()

class User(Base):
    __tablename__=\'user\'
    id=Column(Integer,primary_key=True)
    name=Column(String(32))
    password=Column(String(64))

class Student(Base):
    __tablename__=\'student\'
    id=Column(Integer,primary_key=True)
    name=Column(String(32),nullable=False)
    register_date=Column(DATE,nullable=False)
    gender=Column(String(32),nullable=False)

    def __repr__(self):
        return "<%s name:%s>" %(self.id,self.name)

Base.metadata.create_all(engine) #创建表结构

Session_class=sessionmaker(bind=engine)
#创建与数据库的会话session class，注意，这里返回给session的是这个class，不是实例
Session=Session_class() #生成session实例


#s1=Student(name="s2",register_date="2019-01-08",gender="F")
s2=Student(name="s1",register_date="2019-01-09",gender="M")
Session.add(s2)



#联表查询两张表join-不带外键关系
print(Session.query(User,Student).filter(User.id==Student.id).all())
Session.commit() #现在才统一提交，创新数据