Supplying data for a form re-population from a different model

Question

so I have a tricky issue here I'm not sure how to solve.

1. I have a Provider model that has_many :educational_affiliations
2. EducationalAffiliation belongs_to :institution & belongs_to :provider

I have about 9000 universities in my database, so I'm using the handy-dandy rails3-jquery-autocomplete gem to give me type-ahead support. That's all working great - on TOP of that I'm using cocoon to support the nesting of the :educational_affiliations form inside of the provider's edit form.

So here's where the issue comes — This works great for submitting new affiliation records, (I'm using some jquery to set the :institution_id on the :educational_affiliations_attributes object, works great)

BUT when I return to edit this later, of course the :institution_name isn't populated, because it's not part of the :educational_affiliations model, it's in the :institution model.

Here's what I just tried in my :educational_affiliations, which I assume is the right solution:

class EducationalAffiliation < ActiveRecord::Base
  attr_accessible :degree, :graduation_year, :honors, :institution_name, :institution_id, :provider_id
  belongs_to :institution
  belongs_to :provider

  # attr_accessor :institution_name

  validates :institution_id, :graduation_year, :provider_id, :degree, presence: true

  def institution_name
    Institution.find(institution_id).name
  end

end

(i had it working for saving using the attr_accessor, but I've commented it out for now)

So when I render the edit view with the above, I get a ActiveRecord::RecordNotFound: Couldn't find Institution without an ID error — but when I open a debugger on that statement, the model DOES seem to know the institution_id...so confused why it doesn't pick it up.

Am I just doing this in the worst way possible? I assume there's a dumb solution.. :)

Here's the partial that needs the name populated:

.nested-fields
  = f.input :institution_name, url: autocomplete_institution_name_data_path, as: :autocomplete, :input_html => {:id_element => '#provider_educational_affiliations_institution_id'}
  = f.input :institution_id, as: :hidden
  = f.input :provider_id, as: :hidden, input_html: { value: current_provider.id }
  = link_to_remove_association "Remove Degree", f

Answer 1

Instead of the virtual attribute method, try the following to define the attribute:

delegate :name, :name=, :to => :institute, :prefix => true