在sqlalchemy中查询外键

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

Base = declarative_base()

class User(Base):
    __tablename__ = 'user'
    id = Column(Integer, primary_key=True)
    name = Column(String)
    orders = relationship('Order', back_populates='user')

class Order(Base):
    __tablename__ = 'order'
    id = Column(Integer, primary_key=True)
    user_id = Column(Integer, ForeignKey('user.id'))
    user = relationship('User', back_populates='orders')

from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker

engine = create_engine('数据库连接字符串')
Session = sessionmaker(bind=engine)
session = Session()

orders = session.query(Order).all()
for order in orders:
    print("订单ID:", order.id)
    print("用户ID:", order.user_id)
    print("用户名:", order.user.name)