🐷 An expressive query DSL for Active Record 4 and 5
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README.md

BabySqueel

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biddy piggy

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. ❤️

Installation

Add this line to your application's Gemfile:

gem 'baby_squeel'

And then execute:

$ bundle

Or install it yourself as:

$ gem install baby_squeel

Introduction

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 }

Quick note

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 }

Usage

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
Selects
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"
Wheres
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%')
Orders
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
Joins
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'
Grouping
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)
Functions
Post.selecting { coalesce(author_id, 5).as('author_id_with_default') }
# SELECT coalesce("posts"."author_id", 5) AS author_id_with_default FROM "posts"
Subqueries
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'
# )
Custom SQL Operators
authors = Author.selecting { name.op('||', quoted('-dizzle')).as('swag') }
# SELECT "authors"."name" || '-dizzle' AS swag FROM "authors"

authors.first.swag #=> 'Ray Zane-dizzle'
Querying tables without Active Record models
table = BabySqueel[:some_table]

Post.joining {
  table.on(table.post_id == id)
}.where.has {
  table.some_column == 1
}
Helpers
# 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

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%')

What's what?

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

Migrating from Squeel

Check out the migration guide.

Development

  1. Pick an Active Record version to develop against, then export it: export AR=4.2.6.
  2. Run bin/setup to install dependencies.
  3. Run 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.

Contributing

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

License

The gem is available as open source under the terms of the MIT License.