Get ActiveRecord association count with ease and without worrying about N+1 queries:
Author.all.include_post_count.map(&:post_count)
A small gem for ActiveRecord that allows association counts to be included in your base query.
Add this line to your application's Gemfile:
gem 'association_count'
And then execute:
$ bundle
Or install it yourself as:
$ gem install association_count
Include in specific model
Simply add
class Post < ApplicationRecord
extend AssociationCount
# [...]
end
Include in all models
Rails 5, add it to ApplicationRecord
class ApplicationRecord < ActiveRecord::Base
self.abstract_class = true
# [...]
extend AssociationCount
end
Rails 4, add it to ActiveRecord::Base
ActiveRecord::Base.extend AssociationCount
Full example
class Foo < ActiveRecord::Base
has_many :bars
can_count :bars
end
class Bar < ActiveRecord::Base
belongs_to :foo
end
# Each Foo instance will come with a "preloaded" count method: bar_count
Foo.all.include_bar_count.map(&:bar_count) # only one SQL query executed
# you can also achieve the same with
foos = Foo.all.association_count(Bar)
This works for any has_many
relationship even if it uses non standard foreign keys or is a has_many :x, through: y
.
:information_source: By default we will use left outer join and not distinct.
You can configure this on per model basis
class Foo < ActiveRecord::Base
has_many :bars
can_count :bars, distinct: true, join_type: :joins # can also be left_outer_joins
end
or on a case by case basis
Foo.all.include_bar_count(distinct: false, join_type: :left_outer_joins)
AssociationCount.configure do |config|
config.distinct = false
config.join_type = :joins # or left_outer_joins
end
After checking out the repo, run bin/setup
to install dependencies. Then, 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
to create a git tag for the version, push git commits and tags, and push the .gem
file to rubygems.org.
git checkout -b my-new-feature
)git commit -am 'Add some feature'
)git push origin my-new-feature
)