Question

It is my expectation that when I create a BrickItem, it will have a reference to a Ability. Yet, when the BrickItem is created, abilities_id is null. Why?

My table create:

  create_table "brick_items", :force => true do |t|
  t.integer  "abilities_id"

My Ability migration:

  Ability.create :name => 'my choice'

My controller:

def create
        @brick_item = BrickItem.new(params[:brick_item])
        @brick_item.build_ability(:id => 1)

My model:

  class BrickItem < ActiveRecord::Base
  has_one :ability
end

Answer 1

I’m not sure I fully understand the whole picture, but from the code you’ve shared, it appears there are several problems:

1. You should call the column ability_id, since there’s only one
2. If brick item holds the ability_id, then you should use belong_to and not has_one
3. build_ability will only build a new ability. You should use create_ability.