Python 之 sqlalchemy 外键正反向关联查询

表内容：

代码：

#Author Kangimport sqlalchemyfrom sqlalchemy import create_enginefrom sqlalchemy.ext.declarative import declarative_basefrom sqlalchemy import Column,Integer,String,ForeignKeyfrom sqlalchemy.orm import sessionmaker,relationship#创建对象的基类：Base = declarative_base()#定义User对象：class User(Base):    #表的名字：    __tablename__ = 'user'    #表的结构:    userid = Column(Integer,primary_key=True)    username = Column(String(20))    age = Column(Integer)    department = Column(String(20))    salary = relationship("Salary",backref="test")    #def __repr__(self):    #    return "userid:%s name:%s age:%s department:%s money:%s "%(self.userid,self.username,self.age,self.department,self.salary[0])#定义Salary对象：class Salary(Base):    #表的名字：    __tablename__ = 'salary'    #表的结构:    id = Column(Integer,primary_key=True)    userid = Column(Integer,ForeignKey("user.userid"))    month = Column(Integer)    money = Column(Integer)    def __repr__(self):        return "%s" % (self.money)#初始化数据库连接engine = create_engine("mysql+pymysql://kang:[email protected]/test",encoding="utf-8")#创建session类型DBSession = sessionmaker(bind=engine)#创建session对象session = DBSession()print("Salary表，通过backref反向查询User的姓名信息>>>>>>>>>>>>>>")e1 = session.query(Salary).filter_by(userid=3).first()print(e1.test.username,e1.money)print("user表，正向查询salary工资信息>>>>>>>>>>>>>>>>>>>>>>>>")res = session.query(User).filter_by(username='MingKang').first()print(res.username,res.salary[0])

结果：

Salary表，通过backref反向查询User的姓名信息>>>>>>>>>>>>>>MingKang 12000user表，正向查询salary工资信息>>>>>>>>>>>>>>>>>>>>>>>>MingKang 12000