Is foreign key reference from two different primary key from two different tables valid?

Posted by arundex on Stack Overflow See other posts from Stack Overflow or by arundex
Published on 2012-10-07T09:35:12Z Indexed on 2012/10/07 9:36 UTC
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I have a foreign key that has to refer primary keys of two different tables.

Table 1: animal

       animal_ id (primary key)

Table 2: bird

       bird_ id (primary key)

Table 3: Pet_info

      pet_id,
      type ENUM ('bird', 'animal')
      foreign key (pet_ id) references animal(animal_id), bird(bird_id) 

So, I need to check for pet_id either from animal or bird table depending on the need. Is this valid? Or should I go for some restructuring . . .

NOTE: I referred this . . but I'm not sure whether I have to change my existing design

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