Not sure where (model or controller) to define my find method

(Warning: Clueless Rails Newbie!)

In my show.html.erb for my albums view, I call a public method in my albums controller:

<% albums_feature = find_albums_with_feature(feature.id) %>

It generates a NoMethodError.

So I copied the method into my Album model and tried calling it from the view as:

<% albums_feature = Album.find_albums_with_feature(feature.id) %>

But this also gets a NoMethodError.

Where should I define this method?

For what it's worth, the method looks like this:

  def find_albums_with_feature(feature_id)
    albums_for_feature = Albums.find_by_sql(  
    ["select al.* from albums al, albums_features alfe
    where al.id = alfe.album_id
    and alfe.feature_id = ?", feature_id])
  end

From stackoverflow

• In the Album model. Needs self in front though:

  def self.find_albums_with_feature(feature_id)
  

  pez_dispenser : Why does it need 'self'? In Ruby, you don't need 'self' usually? Anyway, after I followed your suggestion I got: "uninitialized constant Album::Albums" when I called Album.find_albums_with_feature(feature.id) from the view. Did I need something else?

  klew : If you put it in model, than remove "Albums." from "Albums.find...and_so_on".

  Jarrod : The self part is the object the method is for, so from a controller you use Album.method, but when calling the method from within its own model you use self.method. Also: klew's answer is probably the way you'll want to go. It's important in Ruby to treat everything as its own object with its own methods, with proper associations.

• If you want to have method that is accesible from view, you have few options:

  • put it in the model
  • put it in the helper
  • put it in the controller and add a line "helper_method :find_albums_with_feature"

  But I think you can do it better. Firstly, don't put any finding methods in view. Put it in the controller. Secondly, you don't need to specify your own finding method. Probably you have something like this in your models:

  class Album << ActiveRecord::Base
    has_many :albums_features
    has_many :features, :through => :albums_features
  end
  
  class AlbumsFeature << ActiveRecord::Base
    belongs_to :album
    belongs_to :feature
  end
  
  class Feature << ActiveRecord::Base
    has_many :albums_features
    has_many :albums, :through => :albums_features
  end
  

  With it, you can find albums with specific feature like this:

  @feature = Feature.find(id)
  @albums = @feature.albums
  

  or

  @albums = Feature.find(id).albums
  

  and it should be in your controller. In view you should only display results.

  If you are looking for more informations about associations, take a look here: http://guides.rubyonrails.org/association_basics.html. I think it's the best place where you can learn about Rails - at least it is for me.

  pez_dispenser : Wow. Terrific. Thanks.