Question

I’m new with ruby and rails and have been struggling with this issue for a few days. I know I had another association like this elsewhere in my app, but this one just isn’t working.

I have a has_many and belongs_to relationship between my Game model and Character model.

game.rb

has_many :characters

character.rb

belongs_to :game, :foreign_key => 'game_id'

I want to be able to store the game_id in the character and then show the game’s name in the view like this:

<%= @character.game.name %>

But I get this error:

NoMethodError in Characters#show

Showing …/rpglegion/app/views/characters/show.html.erb where line #5 raised:

undefined method `name’ for nil:NilClass

Extracted source (around line #5):

5: <%= @character.game.name %>

Application Trace | Framework Trace | Full Trace

app/views/characters/show.html.erb:5:in >_app_views_characters_show_html_erb___872566584_80495980′
app/controllers/characters_controller.rb:20:in `show’

_characters_controller.rb_

def show
  @character = Character.find(params[:id])
  respond_to do |format| #line 20
    format.html # show.html.erb
    format.xml  { render :xml => @character }
  end
end

I can’t figure out what exactly I’m doing wrong that the associations aren’t working. Can somebody please help me?

Answer 1

First, “game_id” is implied by the belongs_to association, so you can remove the :foreign_key part.

Second, does the @character actually have a game_id set to a game? If not, open a console, find the character you’re looking at, and set it’s game_id to an existing game. For instance:

character = Character.find_by_id(some_character_id)
character.game = Game.find_by_id(some_game_id)
character.save