Rails single table inheritance with reference different columns in different models

Question

How can I have 2 different references columns in 2 models which inherit from a common class using single table inheritance?

I have found this Single Table Inheritance (STI) column associations answer but as it is 10 years ago is there a better solution now in rails?

Problem example: I want something like Consider classes (Animal has type to identify the Lion/Human)

class Animal < ApplicationRecord
    belongs_to :classA
end

class Lion < Animal
    belongs_to :two_legged
end

class Human < Animal
    belongs_to :four_legged
end

So finally I want Lion to belong to classA and two_legged; Human to belong to classA and four_legged

Is there any other better solution than to define all three belongs_to in Animal and making unrelated column nil in Lion & Human ??

This sounds a bit like you want a [polymorphic association](https://guides.rubyonrails.org/association_basics.html#polymorphic-associations) @Rahul. — SRack, Jul 26 '19 at 15:21
All are models - Animal, Lion, Human, two_legged, four_legged — Rahul, Jul 27 '19 at 13:48

score 0 · Answer 1 · edited Sep 26 '21 at 03:44

0

Follow the official doc:

class Animal < ApplicationRecord
    belongs_to :classA
    has_many :lions
    has_many :humans
end

class Lion < ApplicationRecord
    belongs_to :animal
end

class Human < ApplicationRecord
    belongs_to :animal
end

edited Sep 26 '21 at 03:44

michaelrbock

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answered Jul 26 '19 at 12:09

Velusamy Venkatraman

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I am not sure how this answers the question. – engineersmnky Jul 26 '19 at 13:17
two_leg and four_leg is may not be a table. may be it type of animal – Velusamy Venkatraman Jul 26 '19 at 13:24
This solution doesn't use single table inheritance and two_legged and four legged are also models – Rahul Jul 27 '19 at 13:49

Rails single table inheritance with reference different columns in different models

1 Answers1