ruby on rails uninitialized constant error nested resources

Question

I'm new to Ruby on Rails and have not programmed for many years. I'm trying some simple code that is similar to the sample provided in the "Getting Started with Rails" guide for Rails 3.2. Instead of Posts and Comments my models are States and Counties. I've reviewed the code for problems with pluralization, but don't see anything out of place. My system is configured with Rails 4.0 and ruby 1.9.3. I encounter the error after I list the states from the index page. Once the states are listed, I select to show a state, which should allow me to add a County, but instead I get the following error on the page:

uninitialized constant State::County

The code listed with the error is from /app/views/states/show.html.erb

    </p>
    <h2>Add a County:</h2>
    <%= form_for([@state, @state.counties.build]) do |f| %>
       <div class="field">
         <%= f.label :name %><br />
         <%= f.text_field :name %>

I'm providing other MVC files and the DB schema below. Models: state.rb

    class State < ActiveRecord::Base  
      attr_accessible :abbr, :name
      validates :abbr, :presence => true,
               :length => { :maximum => 2 },
               :format => { :with => /\A[A-Z]+\z/,
                  :message => "only 2 uppercase letters allowed" }                    
      validates :name, :presence => true
      has_many :counties, :dependent => :destroy                   
    end

county.rb

    class County < ActiveRecord::Base
      attr_accessible :name, state_id
      validates :name, :presence => true
      belongs_to :state
    end

Views State/show.html.erb

    <p id="notice"><%= notice %></p>
    <p>
      <strong>Abbr:</strong>
      <%= @state.abbr %>
    </p>
    <p>
      <strong>Name:</strong>
      <%= @state.name %>
    </p>
    <h2>Add a County:</h2>
    <%= form_for([@state, @state.counties.build]) do |f| %>
      <div class="field">
      <%= f.label :name %><br />
      <%= f.text_field :name %>
    </div>
    <div class="actions">
      <%= f.submit %>
    </div>
    <% end %>
    <br />
    <%= link_to 'Edit', edit_state_path(@state) %> |
    <%= link_to 'Back', states_path %>

Routes.rb

    resources :states do
      resources :counties
    end

Controllers

counties_controller.rb

    class CountiesController < ApplicationController
      def create
        @state = State.find(params[:state_id])
        @county = @state.counties.create(params[:county])
        redirect_to state_path(@state)
      end
      def destroy
        @state = State.find(params[:state_id])
        @county = @state.counties.find(params[:id])
        @county.destroy
        redirect_to state_path(@state)
      end
    end

states_controller.rb This is a standard file created by rails with the scaffold generator. No changes have been made to this file. If you need it to help with this issue I will post it, but it is rather long.

schema.rb

    ActiveRecord::Schema.define(version: 20141013234441) do
      create_table "counties", force: true do |t|
        t.string   "name"
        t.integer  "state_id"
        t.datetime "created_at"
        t.datetime "updated_at"
      end
      add_index "counties", ["state_id"], name: "index_counties_on_state_id", using: :btree

      create_table "states", force: true do |t|
        t.string   "abbr",       limit: 2, null: false
        t.string   "name"
        t.datetime "created_at"
        t.datetime "updated_at"
      end

end

Any help is appreciated...

Answer 1

Never mind... I found the answer to my own question. I knew it had to be something simple. I was missing a colon in the county.rb file.

Original:

class County < ActiveRecord::Base
  attr_accessible :name, state_id

Corrected:

class County < ActiveRecord::Base
  attr_accessible :name, :state_id