Как реализуется связь Many-to-Many в БД

CREATE TABLE Students (
    id SERIAL PRIMARY KEY,
    name VARCHAR(100)
);

CREATE TABLE Courses (
    id SERIAL PRIMARY KEY,
    title VARCHAR(100)
);

CREATE TABLE StudentCourses (
    student_id INT REFERENCES Students(id),
    course_id INT REFERENCES Courses(id),
    PRIMARY KEY (student_id, course_id)
);

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

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

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