sqlalchemy外键关联

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

engine = create_engine("mysql+pymysql://root:root@10.10.10.147/studydb",
                       encoding='utf-8', echo=True)

Base = declarative_base()


class Student(Base):
    __tablename__ = 'student'
    id = Column(Integer, primary_key=True)
    name = Column(String(32), nullable=False)
    register_date = Column(DATE, nullable=False)

    def __repr__(self):
        return '<%s name:%s>' % (self.id, self.name)


class StudyRecord(Base):
    __tablename__ = 'study_record'
    id = Column(Integer, primary_key=True)
    day = Column(Integer, nullable=False)
    status = Column(String(32), nullable=False)
    stu_id = Column(Integer, ForeignKey('student.id'))

    student = relationship("Student", backref="my_study_record")

    def __repr__(self):
        return '<%s day:%s status:%s>' % (self.student.name, self.day, self.status)


Base.metadata.create_all(engine)

Session_class = sessionmaker(bind=engine)
session = Session_class()

# s1 = Student(name='Alex', register_date='2014-04-25')
# s2 = Student(name='Eric', register_date='2011-04-25')
# s3 = Student(name='Merry', register_date='2017-04-25')
# s4 = Student(name='Rain', register_date='2013-04-25')
#
# study_obj1 = StudyRecord(day=1, status='YES', stu_id=1)
# study_obj2 = StudyRecord(day=2, status='YES', stu_id=1)
# study_obj3 = StudyRecord(day=3, status='YES', stu_id=1)
# study_obj4 = StudyRecord(day=4, status='YES', stu_id=2)
# study_obj5 = StudyRecord(day=5, status='YES', stu_id=2)
# study_obj6 = StudyRecord(day=6, status='YES', stu_id=2)
#
# session.add_all([s1, s2, s3, s4, study_obj1, study_obj2, study_obj3, study_obj4, study_obj5, study_obj6])

stu_obj = session.query(Student).filter(Student.id == "Alex").first()
print(stu_obj.my_study_record)

session.commit()