Rails 5 join table naming conventions – Mark Grealish

Rails 5 join table naming conventions

January 11, 2017 in code

This is a stupid fucking thing, but here we are. My underling and I wasted 40 minutes today re-figuring this out.

Migration:

class PluralSingular < ActiveRecord::Migration[5.0]
  create_join_table :plural, :plural
end

Model:

app/model/foo.rb

class Foo < ApplicationRecord
  has_many :plural_singular
  has_many :plural, through: :plural_singular
end

Join model:

app/model/plural_singular.rb

class PluralSingular < ApplicationRecord
  belongs_to :foo
  belongs_to :bar
end

Harry December 22, 2017 #

It is a stupid thing but I thank you dearly for making this blog post
Chris May 16, 2018 #

Hi Mark,

Thanks for the this, our team was just debating join models as SingularSingular or PluralSingular and I ran across your post. Curious what drove you to decide that PluralSingular is the correct way? Will we miss out on some ActiveRecord magic by using the SingularSingular class name pattern on our join model?
Mark Grealish May 17, 2018 #

Hey Chris, it’s as simple as that’s the Ruby on Rails convention when you don’t give a join table a special name.
Travis Smith May 19, 2019 #

This post has saved my sanity more times than I can count in the past 6 months. Thank you kindly.
John June 19, 2019 #

Current (6/19) Rails Guide implies PluralPlural:

The migration method create_join_table creates an HABTM (has and belongs to many) join table. A typical use would be:

create_join_table :products, :categories

which creates a categories_products table with two columns called category_id and product_id.

See: https://edgeguides.rubyonrails.org/active_record_migrations.html#creating-a-join-table
John June 19, 2019 #

woops…disregard previous comment!

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