|> Marc Anguera

Jun 2013

Introducing Unscoped Associations

Ruby on Rails is a great framework with a lot of built-in options and customizations, specially regarding the data/models layer (Active Record). One of them is the ability to collect instances of a particular class using a default_scope. Very useful to collect “scoped” data by default, but pulling objects via associations is also affected, leading sometimes to weird behavior (think in “soft deletes”).

This library allows you to easily skip the default_scope when navigating through your associations:

belongs_to :user, unscoped: true

Supported associations:

  • belongs_to
  • has_one
  • has_many

More information, source and follow up here.

Installation

Add this line to your Gemfile:

gem 'unscoped_associations'

Scenario usage

From now on, you’re able to use the unscoped option in your association definitions. Basic usage example:

class User < ActiveRecord::Base
  has_many :comments # or , unscoped: false
  has_many :all_comments, class_name: 'Comment',
                          unscoped: true
  has_one  :last_comment, class_name: 'Comment',
                          order: 'created_at DESC',
                          unscoped: true

  default_scope where( active: true )
end

class Comment < ActiveRecord::Base
  belongs_to :user, unscoped: true

  default_scope where( public: true )
end

@user.comments # => return public comments
@user.all_comments # => return all comments skipping default_scope
@user.last_comment # => return last comment skipping default_scope
@comment.user # => return user w/o taking account 'active' flag

Status

Tested on Rails 3.x series and Rails 4.0.0. Originally thought and built for Rails 3, Rails 4 supported.

NOTE: Rails 4 introduces some updates (and more planned for upcoming releases) related to this part. For example, in Rails 4, you are able to customize associations using a scope block, so you can skip default_scope:

class User < ActiveRecord::Base
  has_many :all_comments, -> { where public: [true, flase] }, class_name: 'Comment'
end

Anyway, you can still use unscoped option, if you prefer.

Contributing

Feel free to fork, send ideas, bugs or any comment.