Soft delete records with Paranoia

How to use Paranoia to makes soft deleting records in Ruby on Rails

Luan Nguyen

Oct 17, 2020 · 2 min read

What'll we learn:

Introduction to Paranoia gem
Installation
How to use Paranoia functionality?
Conclusion

Introduction

Paranoia is a gem that allow you to hide and restore records without actually deleting them and can recover them later if you want.
This gem re-implementation of ActsAsParanoid

Installation

Add paranoia gem to Gemfile:

gem 'paranoia', '~> 2.4'

Then run:

bundle install

Create migration to add soft-delete for Post model:

bin/rails generate migration AddDeletedAtToPost deleted_at:datetime:index

The migration will add column deleted_at to Post model:

class AddDeletedAtToPost < ActiveRecord::Migration[6.0]
  def change
    add_column :posts, :deleted_at, :datetime
    add_index :posts, :deleted_at
  end
end

Run migration:

rails db:migrate

== 20201016152809 AddDeletedAtToPost: migrating ====================
-- add_column(:posts, :deleted_at, :datetime)
   -> 0.0333s
-- add_index(:posts, :deleted_at)
   -> 0.0270s
== 20201016152809 AddDeletedAtToPost: migrated (0.0605s) ===========

Usage

Enable this functionality for Post model:

class Post < ActiveRecord::Base
  acts_as_paranoid

  [...]
end

Paranoia will changes the default_scope of model, that mean Post.all will not include the deleted records.

Soft Delete a record:
When we destroy a record, it'll set current timestamp to deleted_at column

post.deleted_at
# => nil
post.destroy
# => post
post.deleted_at
# => [current timestamp] Fri, 16 Oct 2020 15:39:19 UTC +00:00

Restore a record:
It'll update { deleted_at => nil }

post.restore
or
Post.restore(id)

Restore a record and their dependently destroyed Associated records:

post.restore(:recursive => true)
or
Post.restore(id, :recursive => true)

Find a deleted post

Post.find(id)
# => ActiveRecord::RecordNotFound
Post.unscoped.find(id) || Post.with_deleted.find(id)
# => post

Filtering:
Find all records, includes deleted posts:

Post.with_deleted

Find records, exclude deleted posts:

Post.without_deleted

Find only the deleted posts:

Post.only_deleted

Really Delete a Post
If you really want it gone, call really_destroy!:

post.really_destroy!

Conclusion

In this article, I already guided about how to soft-delete records instead of permanent-delete records in database. Paranoia actually is a useful gem, that makes soft deleting easier.