DeletedAt

Hide your "deleted" data (unless specifically asked for) without resorting to default_scope by leveraging in-line sub-selects. (See the Upgrading section)

Requirements

• Ruby 2.3+
• ActiveRecord 4.1+

Installation

Add this line to your application's Gemfile:

gem 'deleted_at'

And then execute:

$ bundle

Or install it yourself as:

$ gem install deleted_at

Usage

Invoking with_deleted_at sets the class up to use the deleted_at functionality.

class User < ActiveRecord::Base
  with_deleted_at

  # the rest of your model code...
end

To work properly, the tables that back these models must have a deleted_at timestamp column.

class AddDeletedAtColumnToUsers < ActiveRecord::Migration

  def change
    add_column :users, :deleted_at, 'timestamp with time zone'
  end

end

If you're starting with a brand-new table, the existing timestamps DSL has been extended to accept deleted_at: true as an option, for convenience. Or you can do it seperately as shown above.

class CreatCommentsTable < ActiveRecord::Migration

  def change
    create_table :comments do |t|
      # ...
      #  to the `timestamps` DSL
      t.timestamps null: false, deleted_at: true
    end
  end

end

Performance

It's recommended (if your database engine supports it) to add partial indexes to the deleted_at columns. Remember that indexes work best when they represent a minority of the rows. It's up to you to determine the best index for your table.

Example 1:

You have a thriving business and your customers love your product and rarely delete their account. You're likely to have way fewer rows WHERE deleted_at IS NOT NULL.

class IndexDeletedAtColumns < ActiveRecord::Migration

  def change
    add_index :users, :deleted_at, where: "deleted_at IS NOT NULL"
  end

end

Example 2:

You use expiring OAuth2 tokens as part of your application's authentication process. As time grows without bound rows WHERE deleted_at IS NULL will pale in comparison.

class IndexDeletedAtColumns < ActiveRecord::Migration

  def change
    add_index :oauth_tokens, :deleted_at, where: "deleted_at IS NULL"
  end

end

Upgrading

If you've used deleted_at prior to v0.5.0, you'll need to migrate your schema. The new version of deleted_at no longer uses views, instead constructing a subselect on the relations. This significantly reduces code polution and monkey patching, as well as reducing the runtime memory usage for rails. Your Database will look (and be) a lot cleaner with no deleted_at views and your ERDs will be much cleaner as well.

Here is an example of a migration for upgrading

require 'deleted_at/legacy'

DeletedAt.disable

class UpgradeDeletedAt < ActiveRecord::Migration
  def up
    # hip hip hooray!
    models.each do |model|
      DeletedAt::Legacy.uninstall(model)
    end
  end

  def down
    # booo hiss
    models.each do |model|
      DeletedAt::Legacy.install(model)
    end
  end

  private

  def models
    [
      User,
      Post
    ]
  end
end

Development

After checking out the repo, run bundle to install dependencies. Then, run bundle exec rspec to run the tests.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/TwilightCoders/deleted_at. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.