Question

There’s probably a simple answer to this, but I’m lost.

I created my first Polymorphic Association today to create an activity field.

Here’s the activity.rb:

class Activity < ActiveRecord::Base

  belongs_to :trackable, :polymorphic => true

end

In the database for activities, I have the columns:

id
name
trackable_id
trackable_type
created_at
updated_at

Here’s the note.rb:

class Note < ActiveRecord::Base

  has_many :activities, :as => :trackable

  after_create :create_an_activity

  def create_an_activity
    self.activities.build(:name => candidate_id)
  end

end

In my index.html.erb view I have:

<% @activities.each do |activity| %>
  <p>activity.name</p>
<% end >

My question is:

Currently, activity.name in the view is outputting the id because I have :name => candidate_id. A note is created for a candidate. But, what I really want it to output is candidate.full_name (which is in the candidates table). However, this doesn’t work because full_name is not in the notes table. It’s in the candidates table. Is there any way to access that? Candidates has_many notes and a note belongs_to a candidate.

Answer 1

enjoyed your skill share with Vin a couple months ago!

I believe what you’re looking for can be accessed by going through the parent association, by calling self -> parent -> attribute:

def create_an_activity
  self.activities.create(:name => self.candidate.full_name)
end

Also correct me if i’m wrong, but unless you are calling a save later on, it seems like self.activities.create is what you are looking for instead of .build