sqlalchemy--m2m

这一块先建个表， 后面再讨论

# -*- coding:utf-8 -*-
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import create_engine, Column, String, Integer, ForeignKey, UniqueConstraint
from sqlalchemy.orm import sessionmaker, relationship


engine = create_engine("sqlite:///test_s1.db")
# 创建数据库连接
session =sessionmaker(bind=engine)()

# 创建表
Base = declarative_base()

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

class Course(Base):
    __tablename__ = 'course'
    id = Column(Integer, primary_key=True)
    title = Column(String(32), index=True, nullable=False)

class Student2Course(Base):
    __tablename__ = 'student2course'
    id = Column(Integer, primary_key=True)
    student_id = Column(Integer, ForeignKey('student.id'))
    course_id = Column(Integer, ForeignKey('course.id'))
    __table_args__ = (
        UniqueConstraint('student_id', 'course_id', name='uix_st_cou'),
    )

def create_all():
    Base.metadata.create_all(engine)

def drop_all():
    Base.metadata.drop_all(engine)

if __name__ == '__main__':
    create_all()
    session.close()