Have you ever used the Squeel gem? It's a really nice way to build complex queries. However, Squeel monkeypatches Active Record internals, because it was aimed at enhancing the existing API with the aim of inclusion into Rails. However, that inclusion never happened, and it left Squeel susceptible to breakage from arbitrary changes in Active Record, eventually burning out the maintainer.
BabySqueel provides a Squeel-like query DSL for Active Record while hopefully avoiding the majority of the version upgrade difficulties via a minimum of monkeypatching. :heart:
Add this line to your application's Gemfile:
gem 'baby_squeel'
And then execute:
$ bundle
Or install it yourself as:
$ gem install baby_squeel
With Active Record, you might write something like this:
Post.where('created_at >= ?', 2.weeks.ago)
But then someone tells you, "Hey, you should use Arel!". So you convert your query to use Arel:
Post.where(Post.arel_table[:created_at].gteq(2.weeks.ago))
Well, that's great, but it's also pretty verbose. Why don't you give BabySqueel a try:
Post.where.has { created_at >= 2.weeks.ago }
BabySqueel's blocks use instance_eval
, which means you won't have access to your instance variables or methods. Don't worry, there's a really easy solution. Just give arity to the block:
Post.where.has { |post| post.created_at >= 2.weeks.ago }
Okay, so we have some models:
class Post < ActiveRecord::Base
belongs_to :author
has_many :comments
end
class Author < ActiveRecord::Base
has_many :posts
has_many :comments, through: :posts
end
class Comment < ActiveRecord::Base
belongs_to :post
end
Post.selecting { (id + 5).as('id_plus_five') }
# SELECT ("posts"."id" + 5) AS id_plus_five FROM "posts"
Post.selecting { id.sum }
# SELECT SUM("posts"."id") FROM "posts"
Post.joins(:author).selecting { [id, author.id] }
# SELECT "posts"."id", "authors"."id" FROM "posts"
# INNER JOIN "authors" ON "authors"."id" = "posts"."author_id"
Post.where.has { title == 'My Post' }
# SELECT "posts".* FROM "posts"
# WHERE "posts"."title" = 'My Post'
Post.where.has { title =~ 'My P%' }
# SELECT "posts".* FROM "posts"
# WHERE ("posts"."title" LIKE 'My P%')
Author.where.has { (name =~ 'Ray%') & (id < 5) | (name.lower =~ 'zane%') & (id > 100) }
# SELECT "authors".* FROM "authors"
# WHERE ("authors"."name" LIKE 'Ray%' AND "authors"."id" < 5 OR LOWER("authors"."name") LIKE 'zane%' AND "authors"."id" > 100)
Post.joins(:author).where.has { author.name == 'Ray' }
# SELECT "posts".* FROM "posts"
# INNER JOIN "authors" ON "authors"."id" = "posts"."author_id"
# WHERE "authors"."name" = 'Ray'
Post.joins(author: :posts).where.has { author.posts.title =~ '%fun%' }
# SELECT "posts".* FROM "posts"
# INNER JOIN "authors" ON "authors"."id" = "posts"."author_id"
# INNER JOIN "posts" "posts_authors" ON "posts_authors"."author_id" = "authors"."id"
# WHERE ("posts_authors"."title" LIKE '%fun%')
Post.ordering { [id.desc, title.asc] }
# SELECT "posts".* FROM "posts"
# ORDER BY "posts"."id" DESC, "posts"."title" ASC
Post.ordering { (id * 5).desc }
# SELECT "posts".* FROM "posts"
# ORDER BY "posts"."id" * 5 DESC
Post.select(:author_id).group(:author_id).ordering { id.count.desc }
# SELECT "posts"."author_id" FROM "posts"
# GROUP BY "posts"."author_id"
# ORDER BY COUNT("posts"."id") DESC
Post.joins(:author).ordering { author.id.desc }
# SELECT "posts".* FROM "posts"
# INNER JOIN "authors" ON "authors"."id" = "posts"."author_id"
# ORDER BY "authors"."id" DESC
Post.joining { author }
# SELECT "posts".* FROM "posts"
# INNER JOIN "authors" ON "authors"."id" = "posts"."author_id"
Post.joining { [author.outer, comments] }
# SELECT "posts".* FROM "posts"
# LEFT OUTER JOIN "authors" ON "authors"."id" = "posts"."author_id"
# INNER JOIN "comments" ON "comments"."post_id" = "posts"."id"
Post.joining { author.comments }
# SELECT "posts".* FROM "posts"
# INNER JOIN "authors" ON "authors"."id" = "posts"."author_id"
# INNER JOIN "posts" "posts_authors_join" ON "posts_authors_join"."author_id" = "authors"."id"
# INNER JOIN "comments" ON "comments"."post_id" = "posts_authors_join"."id"
Post.joining { author.outer.comments.outer }
# SELECT "posts".* FROM "posts"
# LEFT OUTER JOIN "authors" ON "authors"."id" = "posts"."author_id"
# LEFT OUTER JOIN "posts" "posts_authors_join" ON "posts_authors_join"."author_id" = "authors"."id"
# LEFT OUTER JOIN "comments" ON "comments"."post_id" = "posts_authors_join"."id"
Post.joining { author.comments.outer }
# SELECT "posts".* FROM "posts"
# INNER JOIN "authors" ON "authors"."id" = "posts"."author_id"
# LEFT OUTER JOIN "posts" "posts_authors_join" ON "posts_authors_join"."author_id" = "authors"."id"
# LEFT OUTER JOIN "comments" ON "comments"."post_id" = "posts_authors_join"."id"
Post.joining { author.outer.posts }
# SELECT "posts".* FROM "posts"
# LEFT OUTER JOIN "authors" ON "authors"."id" = "posts"."author_id"
# INNER JOIN "posts" "posts_authors" ON "posts_authors"."author_id" = "authors"."id"
Post.joining { author.on((author.id == author_id) | (author.name == title)) }
# SELECT "posts".* FROM "posts"
# INNER JOIN "authors" ON ("authors"."id" = "posts"."author_id" OR "authors"."name" = "posts"."title")
Post.joining { |post| post.author.as('a').on { (id == post.author_id) | (name == post.title) } }
# SELECT "posts".* FROM "posts"
# INNER JOIN "authors" "a" ON ("a"."id" = "posts"."author_id" OR "a"."name" = "posts"."title")
Picture.joining { imageable.of(Post) }
# SELECT "pictures".* FROM "pictures"
# INNER JOIN "posts" ON "posts"."id" = "pictures"."imageable_id" AND "pictures"."imageable_type" = 'Post'
Picture.joining { imageable.of(Post).outer }
# SELECT "pictures".* FROM "pictures"
# LEFT OUTER JOIN "posts" ON "posts"."id" = "pictures"."imageable_id" AND "pictures"."imageable_type" = 'Post'
Post.selecting { id.count }.grouping { author_id }.when_having { id.count > 5 }
# SELECT COUNT("posts"."id") FROM "posts"
# GROUP BY "posts"."author_id"
# HAVING (COUNT("posts"."id") > 5)
Post.selecting { coalesce(author_id, 5).as('author_id_with_default') }
# SELECT coalesce("posts"."author_id", 5) AS author_id_with_default FROM "posts"
Post.joins(:author).where.has {
author.id.in Author.select(:id).where(name: 'Ray')
}
# SELECT "posts".* FROM "posts"
# INNER JOIN "authors" ON "authors"."id" = "posts"."author_id"
# WHERE "authors"."id" IN (
# SELECT "authors"."id" FROM "authors"
# WHERE "authors"."name" = 'Ray'
# )
Post.where.has {
exists Post.where.has { author_id == 1 }
}
# SELECT "posts".* FROM "posts"
# WHERE (
# EXISTS(
# SELECT "posts".* FROM "posts"
# WHERE "posts"."author_id" = 1
# )
# )
authors = Author.selecting { name.op('||', quoted('-dizzle')).as('swag') }
# SELECT "authors"."name" || '-dizzle' AS swag FROM "authors"
authors.first.swag #=> 'Ray Zane-dizzle'
table = BabySqueel[:some_table]
Post.joining {
table.on(table.post_id == id)
}.where.has {
table.some_column == 1
}
Given this polymorphism:
# app/models/picture.rb
belongs_to :imageable, polymorphic: true
# app/models/post.rb
has_many :pictures, as: :imageable
The query might look like this:
Picture.
joining { imageable.of(Post) }.
selecting { imageable.of(Post).id }
# SQL Literals
Post.select('1 as one').ordering { sql('one').desc }
# Quoting
Post.selecting { title.op('||', quoted('diddly')) }
# Functions
Post.selecting { func('coalesce', id, 1) }
Sifters are like little snippets of conditions that can take arguments.
class Post < ActiveRecord::Base
sifter :funny do
title == 'rabies'
end
end
class Author < ActiveRecord::Base
sifter :name_contains do |string|
name =~ "%#{string}%"
end
end
Post.joins(:author).where.has {
sift(:funny) | author.sift(:name_contains, 'blergh')
}
# SELECT "posts".* FROM "posts"
# INNER JOIN "authors" ON "authors"."id" = "posts"."author_id"
# WHERE ("posts"."title" = 'rabies' OR "authors"."name" LIKE '%blergh%')
The following methods give you access to BabySqueel's DSL:
BabySqueel | Active Record Equivalent |
---|---|
selecting |
select |
ordering |
order |
joining |
joins |
grouping |
group |
where.has |
where |
when_having |
having |
Check out the migration guide.
export AR=6.1.4
.bin/setup
to install dependencies.rake
to run the specs.You can also run bin/console
to open up a prompt where you'll have access to some models to experiment with.
Bug reports and pull requests are welcome on GitHub at https://github.com/rzane/baby_squeel.
The gem is available as open source under the terms of the MIT License.