Rails: NameError uninitialized constant on Database Relationship

Question

I have a model called "cube," which represents a collection of trading cards:

app/models/cube.rb

class Cube < ApplicationRecord
  has_many :cubecards
  validates :name, length: { in: 3..30 }
end

As you can see, this model has a has_many relationship with cube_cards:

app/models/cube_card.rb

class CubeCard < ApplicationRecord
  belongs_to :cube
end

While following this rails guide for help creating this relationship, the code references this form style:

<%= form_with(model: [ @article, @article.comments.build ], local: true) do |form| %>

For testing purposes, I just want people to input a number that corresponds with the card ID, so I have the following form:

app/views/cubes/show.html.erb

<%= form_with(model: [ @cube, @cube.cubecards.build ], local: true) do |form| %>
  <p>
    <%= number_field(:card, :id, in: 1.0..8000.0, step: 1) %>
  </p>
  <p>
    <%= form.submit %>
  </p>
<% end %>

The problem is, @cube.cubecards.build is giving me trouble: rails throws an uninitialized constant error for Cube::CubeCard.

In other threads, I noticed that plurality has been a common issue, but I can't find anything that would be a problem here.

I also noticed that this fellow had a similar issue, but as far as I can tell the accepted solution does not apply to my code and the highly-voted solutions are about the controller. Here is my cube cards controller:

app/controllers/cube_cards_controller.rb

class CubeCardsController < ApplicationController
  def create
    @cube = Cube.find(params[:cube_id])
    @cubecard = @cube.cubecards.create(cubecard_params)
    redirect_to cube_path(@cube)
  end

  private
    def cubecard_params
      params.require(:cubecard).permit(:card)
    end
end

To clarify once more, a cube can have many cube_cards.

I have also tried changing the plurality of cubecard to cubecards, adding the underscore (cubecard -> cube_card and cube_cards), and even the capitalization cubecard -> CubeCard and CubeCards to no avail.

The tutorial I'm following seems to skip right on through to the form without a single issue, so I know that, being a newbie, I must be making some elementary mistake, but I've been working for about a day now with no apparent solution.

I'm running this locally on a Windows 7 machine, with plans to migrate it to a web host once complete.

If it's helpful, I've posted the code on github.

NameError in Cubes#show

Showing C:/Sites/pokecube/app/views/cubes/show.html.erb where line #25 raised:

uninitialized constant Cube::Cubecard

Extracted source (around line #25):

<p>
  Add a Card:
  <%= form_with(model: [ @cube, @cube.cubecards.build ], local: true) do |form| %>
  <p>
    <%= number_field(:card, :id, in: 1.0..8000.0, step: 1) %>
  </p>

Also, my console spits out the following error:

Completed 500 Internal Server Error in 69ms (ActiveRecord: 1.0ms)

ActionView::Template::Error (uninitialized constant Cube::Cubecard):
22:
23: <p>
24:   Add a Card:
25:   <%= form_with(model: [ @cube, @cube.cubecards.build ], local: true) do |form| %>
26:   <p>
27:     <%= number_field(:card, :id, in: 1.0..8000.0, step: 1) %>
28:   </p>

app/views/cubes/show.html.erb:25:in `_app_views_cubes_show_html_erb___540381856_44810532'

Answer 1

I found a solution to this issue. Unfortunately, I've fallen into a lot of the same trappings as people who have asked similar questions before me: the issue here stems from improper naming of my variables.

I was able to fix the code by changing @cube.cubecards to @cube.cube_cards

Additionally, in the params, I changed :cubecard to :cube_card

As it turns out, the only time I should have used cubecard as all one word is in the Class declarations at the beginning of each file. Every thing else references the table cube_cards, and as such should be spelled exactly in that manner.