"""班级 <-> 老师 多对多中间表。

单独放一个文件是为了让 clazz.py / teacher.py 都能引用它，
又不会互相 import 形成环。
"""

from __future__ import annotations

from sqlalchemy import Column, ForeignKey, Table

from app.model.base import Base

class_teachers = Table(
    "class_teachers",
    Base.metadata,
    Column("class_id", ForeignKey("clazz.id", ondelete="CASCADE"), primary_key=True, comment="班级ID"),
    Column("teacher_id", ForeignKey("teacher.id", ondelete="CASCADE"), primary_key=True, comment="老师ID"),
    comment="班级-授课老师 关联表（一个班多个授课老师，一个老师带多个班）",
)