Atomically

atomically is a Ruby Gem for you to write atomic query with ease.

Supports Rails 3.2, 4.2, 5.0, 5.1, 5.2.

Installation

Add this line to your application's Gemfile:

gem 'atomically'

And then execute:

$ bundle

Or install it yourself as:

$ gem install atomically

Usage

create_or_plus

Import an array of records. When key is duplicate, plus the old value with new value. It is useful to add items to user when user_items may not exist.

First two args (columns, values) are the same with the import method.

Example:

user = User.find(2)
item1 = Item.find(1)
item2 = Item.find(2)

columns = [:user_id, :item_id, :quantity]
values = [[user.id, item1.id, 3], [user.id, item2.id, 2]]
on_duplicate_update_columns = [:quantity]

UserItem.atomically.create_or_plus(columns, values, on_duplicate_update_columns)

before

after

pay_all

Reduce the quantity of items and return how many rows and updated if all of them is enough. Do nothing and return zero if any of them is not enough.

Example:

user.user_items.atomically.pay_all({ item1.id => 4, item2.id => 3 }, [:quantity], primary_key: :item_id)

update

Updates the attributes of the model from the passed-in hash and saves the record. The difference between this method and ActiveRecord#update is that it will add extra WHERE conditions to prevent race condition.

Example:

class Arena < ApplicationRecord
  def atomically_close!
    atomically.update(closed_at: Time.now)
  end

  def close!
    update(closed_at: Time.now)
  end
end

# arena.atomically_close!
UPDATE `arenas` SET `arenas`.`closed_at` = '2018-11-27 03:44:25', `updated_at` = '2018-11-27 03:44:25'
WHERE `arenas`.`id` = 1752 AND `arenas`.`closed_at` IS NULL

# arena.close!
UPDATE `arenas` SET `arenas`.`closed_at` = '2018-11-27 03:44:25', `updated_at` = '2018-11-27 03:44:25'
WHERE `arenas`.`id` = 1752

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake test DB=mysql to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/khiav223577/atomically. 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.