0

For single table inheritance, how do you force Rails to use an integer column for the 'type' column instead of string?

DevelopingChris
  • 39,797
  • 30
  • 87
  • 118
Orion
  • 61
  • 1
  • 6
  • 1
    It's my experience that when you start putting your fingers so deep into the internals is that you usually eventually wish you didn't – bbozo Dec 01 '15 at 16:46

2 Answers2

1

You can override the methods Rails uses to convert the table name to class name and vice versa:

The relevant methods are find_sti_class which is responsible for the translating the value stored in the type column to the respective ActiveRecord model and sti_name which is responsible for retriving the value stored in type column given an ActiveRecord subclass.

You can override them like this: 

class Institution::Base < ActiveRecord::Base

  ALLOWED_CLASSES = %w[Institution::NonProfit Institution::Commercial]

  class << self

    def find_sti_class type_name
      idx = type_name.to_i
      super if idx == 0
      ALLOWED_CLASSES[idx-1].constantize
    rescue NameError, TypeError
      super
    end

    def sti_name
      idx = ALLOWED_CLASSES.index(self.name)
      if idx.nil?
        super
      else
        idx + 1
      end
    end

  end

end

I have written a post elaborating this in more detail.

lorefnon
  • 12,875
  • 6
  • 61
  • 93
0

You would have to find the part of ActiveRecord responsible for handling the "type" column and monkey patch it, i.e. override how it worked from within your application.

John Topley
  • 113,588
  • 46
  • 195
  • 237