ActiveModel::MissingAttributeError: can't write unknown attribute `ad_id' with FactoryGirl

Question

I have the following models:

class Ad < ActiveRecord::Base
  belongs_to :page

  has_one :image
  has_one :logo
end

class Page < ActiveRecord::Base
           


        

Answer 1

When you say:

has_one :image

Rails expects you to define an ad_id field at the images table. Given the way your associations are organised, I assume you have an image_id and a logo_id a the ads table so instead of:

class Ad < ActiveRecord::Base
  belongs_to :page

  has_one :image
  has_one :logo
end

You probably mean:

class Ad < ActiveRecord::Base
  belongs_to :page
  belongs_to :image
  belongs_to :logo
end

If that's not the case then you need to add ad_id columns to both Image and Logo.

Answer 2

Check your test database.

In my case, sometimes I did not modify the columns in the test database after modifying the development database after an incorrect migration.

Answer 3

If you are getting this error while running the specs, it may be the newly added field that are not migrated in the test environment. So migrate it in the test environment with the below command

rake db:migrate db:test:prepare

Answer 4

I ran into this same error and it took a while to figure out a fix. Just in case this helps someone else in the future, here's my scenario and what worked for me. Class names have been changed as this is for work:

I had 2 namespaced models:

Pantry::Jar
has_many :snacks, class_name: Pantry::Snack
accepts_nested_attributes_for :snacks

Pantry::Snack
belongs_to :pantry_jar, class_name: Pantry::Jar

When I would create a new jar with new snacks, I would get:

ActiveModel::MissingAttributeError: can't write unknown attribute `jar_id'

The fix was to change the has_many to be more explicit about the foreign key:

has_many :snacks, class_name: Pantry::Snack, foreign_key: :pantry_jar_id