How to create nested objects using accepts_nested_attributes_for

Question

I\'ve upgraded to Rails 2.3.3 (from 2.1.x) and I\'m trying to figure out the accepts_nested_attributes_for method. I can use the method to update existing nested o

Answer 1

This is a common, circular dependency issue. There is an existing LightHouse ticket which is worth checking out.

I expect this to be much improved in Rails 3, but in the meantime you'll have to do a workaround. One solution is to set up a virtual attribute which you set when nesting to make the validation conditional.

class Note < ActiveRecord::Base
  belongs_to :product
  validates_presence_of :product_id, :unless => :nested
  attr_accessor :nested
end

And then you would set this attribute as a hidden field in your form.

<%= note_form.hidden_field :nested %>

That should be enough to have the nested attribute set when creating a note through the nested form. Untested.