FOREIGN KEY 约束的“多态性”

表中有这样一个字段：

room_id INT NOT NULL CONSTRAINT room_id_ref_room REFERENCES room

我有三张两张桌子，分为两种房间：standard_room and family_room

如何做这样的事情：

room_id INT NOT NULL CONSTRAINT room_id_ref_room REFERENCES standard_room or family_room

I mean, room_id应该参考either standard_room or family_room.
可以这样做吗？

这是我一直在使用的模式。

CREATE TABLE room (
    room_id serial primary key,
    room_type VARCHAR not null,

    CHECK CONSTRAINT room_type in ("standard_room","family_room"),
    UNIQUE (room_id, room_type)
);

CREATE_TABLE standard_room (
    room_id integer primary key,
    room_type VARCHAR not null default "standard_room",

    FOREIGN KEY (room_id, room_type) REFERENCES room (room_id, room_type),
    CHECK CONSTRAINT room_type  = "standard_room"
);
CREATE_TABLE family_room (
    room_id integer primary key,
    room_type VARCHAR not null default "family_room",

    FOREIGN KEY (room_id, room_type) REFERENCES room (room_id, room_type),
    CHECK CONSTRAINT room_type  = "family_room"
);

也就是说，“子类”通过类型鉴别器列指向超类（这样指向的基类是正确的类型，并且超类的主键与子类相同） 。