Creating an association with accepts_nested_attributes_for

rubyonrails-talk
1

I have 2 models, Category and LineItemTypes

There are already plenty existing of both, it is now a requirement for them to be associated. Being many LineItemTypes for every Category.

I have added accepts_nested_attributes_for :line_item_types on Category

I've tried using a hidden_field on a form to create a list of existing associated LineItemTypes:

- form_for @category do |form|   %ul#categorised     - form.fields_for :line_item_types do |line_item_types|       -categorised.each do |l|         %li           =l.description           =line_item_types.hidden_field :category_id

  =form.submit

If I add an item to that list, I get errors saying that a LineItemType for that Category can't be found. I thought accepts_nested_attributes_for would add the association if it doesn't exist. Or is it only for 'creating' new records and modifying existing relationships, not creating new relationships.

a.update_attributes({:line_item_types_attributes => [{:id => 2767}, {:id => LineItemType.find(2).id}]}) ActiveRecord::RecordNotFound: Couldn't find LineItemType with ID=2 for Category with ID=1

Any ideas without having to write something to traverse the resulting form params and create the associations? Or an even easier way to achieving this? I have an existing association with

2

Probably a silly question. Have you declared the belongs_to and has_many associations?

3

Hehe not a silly question, yes, I have, I also got a recommendation to try using the :inverse_of argument on the relationships too. Which didn't haven any effect on the problem.

I've come to the conclusion that accepts_nested_attributes_for works kinda like url_for... Where the presence of ID makes it assume the relationship exists. Rendering accepts_nested_attributes_for not suitable for what I want to do.

I've worked around this with a before filter:

def find_line_item_types     params[:category][:line_item_types] = LineItemType.find(params[:category][:line_item_types].collect { |a| a[0].to_i }) if params[:category] and params[:category][:line_item_types]   end

Thanks for replying! :slight_smile: