Ruby on Rails: uninitialized constant, NameError

Question

Hello I am trying to solve a name error in a RAILS application. I am working on an interface which consists in a map with tiles associated to a certain number of projects.

I have the following models: area.rb

class Area < ActiveRecord::Base
  attr_accessible :map_file_name, :tile_file_name, :alt, ...

  has_many :species
  has_many :maps

end

map.rb ,

class Map < ActiveRecord::Base
  attr_accessible :alt, :file_name, :detail, :area_id

  belongs_to :area
end

and specie.rb

class Specie < ActiveRecord::Base
  attr_accessible :area_id, :author_id, :name, :pwclass, :pwfamily, :txtlandscape, :txtpod, :map

  has_one :author
  belongs_to :area

end

When I try to call the resource in IRB or in a view I get the name error output. I changed specie to field and species to fields , and it works with the same configuration.

I checked and Ruby pluralises specie correctly to species .

How can I get specie to work?

UPDATE : backtrace

Started GET "/projects/show/1" for 127.0.0.1 at Fri Mar 23 13:02:07 +0100 2018
Connecting to database specified by database.yml
Processing by ProjectsController#show as HTML
  Parameters: {"id"=>"1"}
  [1m[36mArea Load (1.8ms)[0m  [1mSELECT 'areas'.* FROM 'areas' WHERE 'areas'.'id' = ? LIMIT 1[0m  [["id", "1"]]
  [1m[35mMap Load (0.4ms)[0m  SELECT 'maps'.* FROM 'maps' WHERE 'maps'.'area_id' = 1
  Rendered projects/show.html.erb (28.1ms)
Completed 500 Internal Server Error in 108ms

ActionView::Template::Error (uninitialized constant Area::Species):
    28:         end %>
    29: <% else %>
    30: <% end %>
    31: <% for specie in @area.species %>
    32: <div class="speciesmap">
    33:   <div id="tile_menu">
    34:     <a onclick="ArticleRequest('/article/show/area-07.html', 'ATLAS-06');"><img src="images/MAP/GUADALQUIVIR_MAP-BUTTONS-TILE-specie.svg" onMouseOver="this.src='images/MAP/estuario_area_136x85px-blck.svg'" onMouseOut="this.src='images/MAP/GUADALQUIVIR_MAP-BUTTONS-TILE-specie.svg'" alt="Specie"></a>
  app/views/projects/show.html.erb:31:in '_app_views_projects_show_html_erb__1608931551_2294133420'
  app/controllers/projects_controller.rb:22:in `show'


  Rendered /Users/xxx/.rvm/gems/ruby-1.8.7-p374@ccc/gems/actionpack-3.2.5/lib/action_dispatch/middleware/templates/rescues/_trace.erb (0.7ms)
  Rendered /Users/xxx/.rvm/gems/ruby-1.8.7-p374@ccc/gems/actionpack-3.2.5/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb (0.6ms)
  Rendered /Users/xxx/.rvm/gems/ruby-1.8.7-p374@ccc/gems/actionpack-3.2.5/lib/action_dispatch/middleware/templates/rescues/template_error.erb within rescues/layout (40.4ms)

Answer 1

Update the relation in your Area class to:

    has_many :species, :class_name => 'Specie'

Then @area.species should work.

Answer 2

As @max highlighted in the comments. The problem here is that species "is the same in both singular and plural".

The two solutions are either to use species as the model name or to declare a class name of "specie" in the related models.

I tried both, both are working. In the end I opted for @max's advice.