SQLAlchemy对于一个表中有多个外键该怎么定义

Question

如果一个表中有多个外键，例如：有学生表、课程表和分数表，想我这样定义是否正确？

class Student(Base):
    __tablename__ = 'students'
    id = Column(Integer, primary_key=True)
    name = Column(String(20), nullable=False, index=True)
    sex = Column(Integer, nullable=True)
    score = relationship('Score', backref='student')

class Subject(Base):
    __tablename__ = 'subjects'
    id = Column(Integer, primary_key=True)
    Name = Column(String(10), nullable=False, index=True)
    score = relationship('Score', backref='score')

class Score(Base):
    __tablename__ = 'score'
    id = Column(Integer, primary_key=True)
    score = Column(Integer, nullable=False)
    subject_id = Column(Integer, ForeignKey('subjects.id'))
    student_id = Column(Integer, ForeignKey('students.id'))

如果要同时添加学生信息和分数信息该怎么添加？