Sqlalchemy和连接两个表的多对多关系

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

Base = declarative_base()

# 关联表
student_courses = Table('student_courses', Base.metadata,
    Column('student_id', Integer, ForeignKey('students.id')),
    Column('course_id', Integer, ForeignKey('courses.id'))
)

class Student(Base):
    __tablename__ = 'students'
    id = Column(Integer, primary_key=True)
    name = Column(String)
    courses = relationship("Course", secondary=student_courses, back_populates="students")

class Course(Base):
    __tablename__ = 'courses'
    id = Column(Integer, primary_key=True)
    name = Column(String)
    students = relationship("Student", secondary=student_courses, back_populates="courses")

# 创建数据库引擎
engine = create_engine('sqlite:///example.db')
Base.metadata.create_all(engine)

# 创建会话
Session = sessionmaker(bind=engine)
session = Session()

# 添加数据
student1 = Student(name='Alice')
student2 = Student(name='Bob')
course1 = Course(name='Math')
course2 = Course(name='Science')

student1.courses.append(course1)
student1.courses.append(course2)
student2.courses.append(course1)

session.add(student1)
session.add(student2)
session.commit()

# 查询数据
for student in session.query(Student).all():
    print(f"Student: {student.name}")
    for course in student.courses:
        print(f"  Course: {course.name}")

session.close()

for student in session.query(Student).all():
    print(f"Student: {student.name}")
    for course in student.courses:
        print(f"  Course: {course.name}")