Question

Let’s consider the following example:

class Ball < ActiveRecord::Base
  def is_ball?
    true
  end
end

class BlueBall < Ball
  def color
    :blue
  end
end

class RedBall < Ball
  def color
    :red
  end
end

When I do Ball.find(id), is it possible to have an instance of BlueBall returned?

With Ball.where(owner: some_user).to_a could I get an array with BlueBall and RedBall instances?

---

I am looking for a way to explicitly set an STI by using some column other that type.

Answer 1

This could work if it’s possible to rename your classes Red and Blue instead of RedBall and BlueBall

def Ball < ActiveRecord::Base

  self.inheritance_column = :color

  def ball?
    is_a?(Ball)
  end

end

def Red < Ball
  # Red#color would return 'Red'
end

def Blue < Ball
  # Blue#color would return 'Red'
end