Python 之 sqlalchemy 外鍵正反向關聯查詢

表內容：

代碼：

#Author Kang

import sqlalchemy
from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column,Integer,String,ForeignKey
from sqlalchemy.orm import sessionmaker,relationship

#創建對象的基類：
Base = declarative_base()

#定義User對象：
class User(Base):
    #表的名字：
    __tablename__ = 'user'
    #表的結構:
    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])

#定義Salary對象：
class Salary(Base):
    #表的名字：
    __tablename__ = 'salary'
    #表的結構:
    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)

#初始化數據庫連接
engine = create_engine("mysql+pymysql://kang:123456@10.3.152.35/test",encoding="utf-8")

#創建session類型
DBSession = sessionmaker(bind=engine)

#創建session對象
session = DBSession()

print("Salary表，通過backref反向查詢User的姓名信息>>>>>>>>>>>>>>")
e1 = session.query(Salary).filter_by(userid=3).first()
print(e1.test.username,e1.money)

print("user表，正向查詢salary工資信息>>>>>>>>>>>>>>>>>>>>>>>>")
res = session.query(User).filter_by(username='MingKang').first()
print(res.username,res.salary[0])

結果：

Salary表，通過backref反向查詢User的姓名信息>>>>>>>>>>>>>>
MingKang 12000
user表，正向查詢salary工資信息>>>>>>>>>>>>>>>>>>>>>>>>
MingKang 12000