How can I make a polymorphic connection be dependent?

I am trying to make my image_maps get destroyed when either a product 开发者_如何学编程or image is deleted. Here is the code.

class ImageMap < ActiveRecord::Base
  belongs_to :imageable, :polymorphic => true
  belongs_to :image
end

class Product < ActiveRecord::Base
  has_many :image_maps, :as => :imageable
  has_many :images, :through => :image_maps
end

class Image < ActiveRecord::Base
  has_many :image_maps, :as => :imageable, :dependent => :destroy
end

Right now the image_maps do not get destroyed when you delete an image and i still need to figure out how to get it to work for products too.

I think that your dependent should go to the ImageMap model.

If i remember correctly, this is what Rails checks on the associated models to see whether they need to be destroyed.