Is it possible to add a logic Constraint to a Foreign Key?

Question

I\'ve got two tables and I\'ve added a foreign key constraint. Kewl - works great. Now, is it possible to further constrain that relationship against some data in the parent

Answer 1

Have a unique constraint on Animals(AnimalId, AnimalType) Add AnimalType to Mammals, and use a check constraint to make sure it is always 1. Have a FK refer to (AnimalId, AnimalType).