Model Association - ruby-on-rails

Question

Hi I have a little problem with associations, I'm working with Rails 3.2, I want to create a special blog, this blog has many sections and this sections has many articles and an article belongs to a Category. So my models are:
class Article < ActiveRecord::Base
belongs_to :section
belongs_to :category
class Category < ActiveRecord::Base
has_many :articles
class Section < ActiveRecord::Base
has_many :article
So articles belongs_to section, in routes.rb :
resources :sections do
resources :articles
end
Rake Routes:
POST /sections/:section_id/articles(.:format) articles#create
new_section_article GET /sections/:section_id/articles/new(.:format) articles#new
edit_section_article GET /sections/:section_id/articles/:id/edit(.:format) articles#edit
section_article GET /sections/:section_id/articles/:id(.:format) articles#show
PUT /sections/:section_id/articles/:id(.:format) articles#update
DELETE /sections/:section_id/articles/:id(.:format) articles#destroy
sections GET /sections(.:format) sections#index
POST /sections(.:format) sections#create
new_section GET /sections/new(.:format) sections#new
edit_section GET /sections/:id/edit(.:format) sections#edit
section GET /sections/:id(.:format) sections#show
PUT /sections/:id(.:format) sections#update
DELETE /sections/:id(.:format) sections#destroy
So my question is How do I create a Categories_controller with index and show action.
to show the articles that belongs to that category, and have a link_to in views(Category#show) for the articles path.

Answer 1

Assuming that you do need nested routes to fit your domain model (ex. articles need to display differently based on whether they are being viewed in the context of a category or a section), then you can just create another set of nested routes like so:
routes.rb
resources :categories, only: [:index, :show] do
resources :articles
end
That will set up routes to find your categories and articles by categories, but you will have to fork your logic in your ArticlesController on params[:category_id] or params[:section_id] like so:
class ArticlesController < ApplicationController
def index
if params[:section_id]
# handle section_articles_path to display articles by section
elsif params[:category_id]
# handle category_articles_path to display articles by category
else
# handle articles_path to display all articles (assuming you have resources :articles in routes)
end
end
# ...
end
The link to show an article based on a category will then use the generated route helper methods created for you.
categories/show.html.erb
<ul>
<% #category.articles.each do |article| %>
<li><%= link_to article.title, category_article_path(#category, article) %></li>
<% end %>
</ul>
You could then, of course, refactor the view code to render the collection as its own partial rather than manually iterating, but I'll leave it at that for now...
If you don't need to handle the context differently (accessing an article through a section versus a category), I'd recommend just setting up three basic routes (:articles, :sections, :categories) and going from there.

Answer 2

It's Very much simple
match 'catagories' => "catagories#index" and match 'catagories/show/:id' => "catagories#show"
In show action #articles = Article.where("category_id",params[:id])
#articles = Article.where("category_id",params[:id]) This will solve your purpose