overrides the default resource identifier :id

• Problem: wanted to make the url like /resources/other_identifier rather than the default id identifier /resources/123
• Solution: use param
  • param: overrides the default resource identifier
  • Using rake routes CONTROLLER=controller_name command to check the overridden identifier, Rails may add prefix automatically

# routes.rb 
  resources :restaurants , param: :code do
    resources :register, only: :create
  end
# generated route => /restaurants/:restaurant_code/register

# controller
params[:restaurant_code]
#=> retrieve the overrides identifier value

Reference

• 4.10 Overriding Named Route Parameters