BabySqueel 🐷

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:

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'
# )

Exists

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
#   )
# )

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
}

Polymorphism

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 }

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=7.2.2.
2. Run bin/setup to install dependencies.
3. Run rake to run the specs.

One-liner to run the specs with different rails versions:

export AR='~> 7.1.6'; rm Gemfile.lock; bin/setup; rake
export AR='~> 7.2.3'; rm Gemfile.lock; bin/setup; rake
export AR='~> 8.0.4'; rm Gemfile.lock; bin/setup; rake
export AR='~> 8.1.1'; rm Gemfile.lock; bin/setup; rake

You can also run bin/console to open up a prompt where you'll have access to some models to experiment with.

Rails update

1. Update baby_squeel.gemspec
2. Add the version to test matrix build.yml
3. Update development section in the README.md
4. If you need to change the code consider to add a version check methode in version_helper.rb
5. Run the specs with all supported versions
6. Add comment to the unreleased section in CHANGELOG.md

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.