How to create a Select which let's you choose between valid types with single table inheritance in Ruby on Rails

Question

i'm using Single Table Inheritance in ruby on rails to model various animals. So i have a base Animal Class and then i have various subclasses in the models/animal folder.

When the user creates an animal, i want to show a select of the various animal types which allows the user to choose a "valid" animal ( which means one animal for which a class exists ).

How can i do this?

Answer 1

Your two choices are

• Animal.subclasses lists all direct subclasses.
• Animal.descendants returns all subclasses regardless of level.