Getting 'uninitialized constant' error when using delegate in belongs_to in model

Question

Hello.

I'm implementing a view on a model with three tables, one of them join table. Here are the tables:

Recipe:

class Recipe < ActiveRecord::Base
  # validates :name,  :presence => true
  # validates :directions, :presence => true

  # has_and_belongs_to_many :ingradients

  has_many :ingredients_recipes
  has_many :ingredients, :through => :ingredients_recipes

  accepts_nested_attributes_for :ingredients_recipes, :allow_destroy => true
end

Ingredient:

class Ingredient < ActiveRecord::Base
  # has_and_belongs_to_many :recipes

  has_many :ingredients_recipes
  has_many :recipes, :through => :ingredients_recipes

end

And the join table between them:

class IngredientsRecipe < ActiveRecord::Base
  belongs_to :recipes
  belongs_to :ingredients, :foreign_key => "ingredient_id"

  delegate :name, :to => :ingredients

end

This seems to work ok, when I create a new recipe - I can edit the recipe lines and everything runs smoothly. When I create a view to show the Recipe with the Ingredient name from Ingredients table I created a delegate in the join table. However when I try to use the delegate within the view:

  <% @recipe.ingredients_recipes.each do |r| %>
    <%= r.ingredient_id %> <br>  
    <%= r.name %>
  <% end %>

I get the following error:

uninitialized constant IngredientsRecipe::Ingredients

When I remove the <%= r.name %> line it runs without errors. Am I defining the delegate wrongly or what could be causing this?

Answer 1

I believe your belongs_to associations in IngredientsRecipes should be singular, not plural, eg:

class IngredientsRecipe < ActiveRecord::Base
  belongs_to :recipe
  belongs_to :ingredient, :foreign_key => "ingredient_id"

  delegate :name, :to => :ingredient

end

Also, check the case of your class name. It should either be all singular (IngredientRecipe), or all plural (IngredientsRecipes) ... I'm not sure which, but I know it shouldn't be mixed.

Finally, why are you using a join model? If you don't have any other attributes in IngredientsRecipes, just use HABTM like your commented out lines.