Nested Models not working

Urgghhh - Newbie help needed to stop me giving up on Rails.

I have 3 nested models.
Recipe->RecipeParts->RecipeIngredients (to the ingredients index so
maybe 4 levels)

class Recipe < ActiveRecord::Base
  has_many :recipe_parts
  accepts_nested_attributes_for :recipe_parts

class RecipePart < ActiveRecord::Base
  belongs_to :recipe
  has_many :recipe_ingredients
  has_many :ingredients, :through => :recipe_ingredients
  accepts_nested_attributes_for :recipe

class RecipeIngredient < ActiveRecord::Base
  belongs_to :recipe_part
  belongs_to :ingredient

I'm trying to write an edit page for Recipe that includes a list of
RecipeParts - and within that a list of RecipeIngredients (each as a
select list)
<h1>Editing recipe</h1>

<% form_for(@recipe) do |recipe_form| %>

  <% recipe_form.fields_for :recipe_parts do |recipe_part_form| %>
      <% recipe_part_form.fields_for :recipe_ingredients do |rcp_ing| %>
               <p><%= rcp_ing.collection_select( :name,
@ing_list_for_select,:id, :name) %></p>

      <% end %>
     <p><%= recipe_part_form.text_field :title %></p>
     <p><%= recipe_part_form.text_field :description %></p>
  <% end %>
  <%= link_to "Add Part", {:controller => "recipes",:action =>
"add_recipe_part", :id => @recipe.id} %>
  <%= recipe_form.submit "Update" %>
<% end %>
<%= link_to 'Show', @recipe %> |
<%= link_to 'Back', recipes_path %>

The multiple RecipeParts list correctly, but within each part I get 1
selection for the ingredients only, despite the data having a mixture
of 0-3 ingredients for the various parts.

So - my recipe_part_form.fields_for line doesn't seem to be iterating
over the recipe_ingredients properly , and I can't work out why - I
think I'm using the identical structure that I did for the RecipeParts
- which works fine.
Secondly - the collection_select isn't giving me a correct Selected
item - but this could be due to the first problem perhaps.

Sorry if the post is too long/stupid/wrong but Rails/Ruby is proving
to be (BY FAR) the hardest and most obtuse environment I've tried
learning in almost 30 years of programming. After almost 3 months of
online tutorials,books, reading forums etc and experimentation I can't
understand just how little I can get working in Rails.

Ian

Urgghhh - Newbie help needed to stop me giving up on Rails.

I have 3 nested models.
Recipe->RecipeParts->RecipeIngredients (to the ingredients index so
maybe 4 levels)

class Recipe < ActiveRecord::Base
has_many :recipe_parts
accepts_nested_attributes_for :recipe_parts

class RecipePart < ActiveRecord::Base
belongs_to :recipe
has_many :recipe_ingredients
has_many :ingredients, :through => :recipe_ingredients
accepts_nested_attributes_for :recipe

Is that what you meant? Should it be accepts_nested_attributes_for
:recipe_ingredients?

Colin

> class Recipe < ActiveRecord::Base
> has_many :recipe_parts
> accepts_nested_attributes_for :recipe_parts

> class RecipePart < ActiveRecord::Base
> belongs_to :recipe
> has_many :recipe_ingredients
> has_many :ingredients, :through => :recipe_ingredients
> accepts_nested_attributes_for :recipe

Is that what you meant? Should it be accepts_nested_attributes_for
:recipe_ingredients?

Colin

Yes it should be ....for :recipe_ingredients Thank you.
I guess I haven't got to grips with what accept_nested_attributes_for
was doing, or on which side of the relationship it's supposed to go
since I had it on both sides.

So - with the first problem solved it took me 30 seconds to solve the
2nd one - finally I don't feel entirely stupid.

Thanks Colin.
Ian