Change the default polymorphic type-column name

I am using Ruby on Rails 3 and I would like to change the default type-column name used by a polymorphic association.

For example, if I have this class:

class Comment < ActiveRecord::Base
  ...
end

and I implement for that a polymorphic association, I wou开发者_开发技巧ld like to use the type-column names comm_id and comm_type instead of commentable_id and commentable_type. Is it possible? If so, what I have to change for the Comment class?

There's no way in Rails API to override the default column name used for polymorphic associations.

Take a look at this answer for a possible solution.

I did this in rails 6 on my legacy database using the foreign_type: option. This should work for rails >= 4.2.1 (see here)

# booking model
class Booking < ApplicationRecord
  has_many :user_notes, as: :notable, foreign_type: :note_type, foreign_key: :type_id
end
# booking model
# here polymorphic columns are `note_type` and `type_id`
class UserNote < ApplicationRecord
  belongs_to :notable, polymorphic: true, foreign_type: :note_type, foreign_key: :type_id
end

In your case, why not just change the association to:

# Comment
belongs_to :comm, :polymorphic => true

# Everything else
has_many :comments, :as => :comm