# PluckAll
[](http://rubygems.org/gems/pluck_all)
[](https://github.com/khiav223577/pluck_all/actions)
[](http://rubygems.org/gems/pluck_all)
[](https://codeclimate.com/github/khiav223577/pluck_all)
[](https://codeclimate.com/github/khiav223577/pluck_all/coverage)
Pluck multiple columns/attributes in Rails 3, 4, 5, 6, and can return data as hash instead of only array. Also supports `Mongoid`.
This Gem stands on the shoulders of this article: [Plucking Multiple Columns in Rails 3](https://meltingice.dev/2013/06/11/pluck-multiple-columns-rails/).
And modified to support not only Rail 3.
If you have a Rails 3 project, and want to pluck not only one column,
feel free to use this gem and no need to worry about upgrading to Rails 4, 5, 6 in the future will break this.
## Supports
- Ruby 2.2 ~ 2.7, 3.0
- Rails 3.2, 4.2, 5.0, 5.1, 5.2, 6.0, 6.1
## Installation
Add this line to your application's Gemfile:
```ruby
gem 'pluck_all'
```
And then execute:
$ bundle
Or install it yourself as:
$ gem install pluck_all
## Usage
### pluck to array
Behaves the same as `#pluck` method, but you can use it to pluck multiple columns in Rails 3
```rb
User.where('id < 3').pluck_array(:id, :account)
# => [[1, 'account1'], [2, 'account2']]
```
### pluck to hash
Similar to `#pluck` method, but return array of hashes instead.
```rb
User.where('id < 3').pluck_all(:id, :account)
# => [{"id"=>1, "account"=>"account1"}, {"id"=>2, "account"=>"account2"}]
User.where('id < 3').pluck_all(:id, 'account AS name')
# => [{"id"=>1, "name"=>"account1"}, {"id"=>2, "name"=>"account2"}]
User.where('id < 3').pluck_all('id, account AS name')
# => [{"id"=>1, "name"=>"account1"}, {"id"=>2, "name"=>"account2"}]
```
## Support Mongoid
```rb
class User
include Mongoid::Document
field :name, type: String
field :age, type: Integer
end
User.pluck_all(:name, :age)
# => [
# {'name' => 'Pearl Shi' , 'age' => 18},
# {'name' => 'Rumble Huang', 'age' => 20},
# {'name' => 'Khiav Reoy' , 'age' => 20},
# ]
```
## Benchmark
### Compare with `map` and `as_json`
`pluck_all` return raw `hash` data without loading a bunch of records, in that having better performace than using `map` and `as_json`. The following is the benchmark test on 191,093 users, where `users` table have 51 columns.
```rb
user system total real
map 36.110000 61.200000 97.310000 ( 99.535375)
select + map 10.530000 0.660000 11.190000 ( 12.550974)
select + as_json 49.040000 1.120000 50.160000 ( 55.417534)
pluck_all 3.310000 0.100000 3.410000 ( 3.527775)
```
Test by `benchmark-ips` and `limit 100` in each iteration:
```
Warming up --------------------------------------
map 1.000 i/100ms
select + map 28.000 i/100ms
select + as_json 7.000 i/100ms
pluck_all 54.000 i/100ms
Calculating -------------------------------------
map 14.230 (± 0.0%) i/s - 72.000 in 5.065349s
select + map 281.638 (± 4.6%) i/s - 1.428k in 5.081216s
select + as_json 73.241 (± 4.1%) i/s - 371.000 in 5.076235s
pluck_all 539.057 (± 6.7%) i/s - 2.700k in 5.034858s
Comparison:
pluck_all: 539.1 i/s
select + map: 281.6 i/s - 1.91x slower
select + as_json: 73.2 i/s - 7.36x slower
map: 14.2 i/s - 37.88x slower
```
[test script](https://github.com/khiav223577/pluck_all/issues/18)
### Compare with [pluck_to_hash](https://github.com/girishso/pluck_to_hash) gem
`pluck_all` has better performace since it uses raw `hash` data from `ActiveRecord::Base.connection.select_all`, while `pluck_to_hash` uses `pluck` method, which calls `ActiveRecord::Base.connection.select_all` and transfers the raw `hash` data to `array` format, and then transfer the data to `hash` format again. The following benchmark shows the performance difference:
```rb
user system total real
pluck_to_hash 2.960000 0.130000 3.090000 ( 3.421640)
pluck_all 2.160000 0.120000 2.280000 ( 2.605118)
```
Tested by `benchmark-ips` and `limit 1000` in each iteration:
```
Warming up --------------------------------------
pluck_to_hash 7.000 i/100ms
pluck_all 9.000 i/100ms
Calculating -------------------------------------
pluck_to_hash 84.526 (± 4.7%) i/s - 427.000 in 5.065792s
pluck_all 95.133 (± 4.2%) i/s - 477.000 in 5.021555s
Comparison:
pluck_all: 95.1 i/s
pluck_to_hash: 84.5 i/s - 1.13x slower
```
See the [test script](https://github.com/khiav223577/pluck_all/issues/18#issuecomment-325407080) for more details.
## Other Support
### Support globalize gem
```rb
class Post < ActiveRecord::Base
translates :title
end
```
```rb
I18n.locale = :en
Post.pluck_all(:title)
# => [{ 'title' => 'english' }, { 'title' => 'english' }, ...]
I18n.locale = :'zh-TW'
Post.pluck_all(:title)
# => [{ 'title' => '中文' }, { 'title' => '中文' }, ...]
```
### Support Pluck Carrierwave Uploader (if you use carrierwave)
```rb
User.where(xxx).pluck_all(:profile_pic).map{|s| s['profile_pic'] }
```
is the same as
```rb
User.where(xxx).map(&:profile_pic)
```
If the uploader use something like: `model.id`, `model.name`
You may have to send these columns manually:
```rb
User.where(xxx).cast_need_columns(%i[id name]).pluck_all(:id, :name, :profile_pic).map{|s| s['profile_pic'] }
```
## Development
After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake test_active_record` or `rake test_mongoid` 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](https://rubygems.org).
## Contributing
Bug reports and pull requests are welcome on GitHub at https://github.com/khiav223577/pluck_all. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the [Contributor Covenant](http://contributor-covenant.org) code of conduct.
## License
The gem is available as open source under the terms of the [MIT License](http://opensource.org/licenses/MIT).