Callback when objects connect as a habtm relationship

rubyonrails-talk
1

If Product and Category models are in a habtm relationship, i.e.

class Product < ActiveRecord::Base has_and_belongs_to_many :categories end

class Category < ActiveRecord::Base has_and_belongs_to_many :products end

I want a piece of code to be executed every time a product is connected to a category. Where do I put this code? Which callback (and on which model) will be triggered?

Any hints appreciated. Thanks for help.

2

Kazim Zaidi wrote:

If Product and Category models are in a habtm relationship, i.e.

class Product < ActiveRecord::Base   has_and_belongs_to_many :categories end

class Category < ActiveRecord::Base   has_and_belongs_to_many :products end

I want a piece of code to be executed every time a product is connected to a category. Where do I put this code? Which callback (and on which model) will be triggered?

Look into adding :after_add callbacks to the associations:

http://api.rubyonrails.com/classes/ActiveRecord/Associations/ClassMethods.html#M001602