platypush/platypush/entities/devices.py

from sqlalchemy import Column, Integer, Boolean, ForeignKey

from ._base import Entity


class Device(Entity):
    __tablename__ = 'device'

    id = Column(Integer, ForeignKey(Entity.id, ondelete='CASCADE'), primary_key=True)
    reachable = Column(Boolean, default=True)

    __mapper_args__ = {
        'polymorphic_identity': __tablename__,
    }