ActiveScaffold: How to create a drop-down select for polymorphic association?

Question

I'm trying to create a drop-down select box for a polymorphic association with ActiveScaffold.

I have:

class Award
  belongs_to :sponsorship, :polymorphic => :true
end

class Organization
  has_many :awards, :as => :sponsorship
end

class Individual
  has_many :awards, :as => :sponsorship
end

While trying to create a select drop-down box in awards_controller with:

config.columns[:sponsorship].form_ui = :select

I get the following error:

ActionView::TemplateError (uninitialized constant Award::Sponsorship)

I'm not sure if it's something I'm not doing right or what I'm trying to accomplish not directly supported in AS.

Would really appreciate some advice.

Looking for an answer too... Playing with .options= right now — Boris Churzin, Mar 03 '10 at 16:37
Are you able to query the association normally. Does Award.first.sponsorship work? Can you create awards and sponsorships via the console? — Pan Thomakos, Jan 31 '11 at 20:47

score 0 · Answer 1 · answered Jan 28 '11 at 16:51

I'm not familiar with ActiveScaffold... But, a quick pass in their documentation revealed a section about has_many :through which I am familiar with from ActiveRecords... so for what it's worth, is it possible that your polymorphic associations should be written like this?:

class Organization
  has_many :awards, :through => :sponsorship
end

class Individual
  has_many :awards, :through => :sponsorship
end

score 0 · Answer 2 · answered Jan 31 '11 at 20:43

I'm not sure of what you're trying to do, but rails is indeed true when saying that there is no ":sponsorship'.

When polymorphism is used, rails automatically create two columns, in your case : *sponsorship_id* and *sponsorship_type*.

You may want to use one of those.

However, I'm not familiar with ActiveScaffold form_ui, so I cannot help you further.

score 0 · Answer 3 · answered Nov 30 '11 at 13:21

I am getting this error, but only if I have an instance of Award with no sponsorship (my names are different...). So presumably the OP and follow up posters got past this, but for future readers, make sure you don't create an instance of the dependent model when using a polymorphic association with active_scaffold...

ActiveScaffold: How to create a drop-down select for polymorphic association?

3 Answers3