# 57 一对一关系实现 ```text from sqlalchemy.orm import backref class Parent(Base): __tablename__ = 'parent' id = Column(Integer, primary_key=True) child_id = Column(Integer, ForeignKey('child.id')) child = relationship("Child", backref=backref("parent", uselist=False)) class Child(Base): __tablename__ = 'child' id = Column(Integer, primary_key=True) parent_id = Column(Integer, ForeignKey('parent.id')) ```