"""ORM 基类：源库（只读）与目标库（本系统所有）各自独立的 DeclarativeBase。"""
from sqlalchemy.orm import DeclarativeBase


class SourceBase(DeclarativeBase):
    """源库（SOURCE，外部只读）模型基类。"""


class TargetBase(DeclarativeBase):
    """目标库（TARGET，本系统所有）模型基类。"""