ActiveRecord の enum を使ってみる (Rails)

Published: 2020-03-14

やったこと

ActiveRecord の enum を使ってみます。

確認環境

$ ruby --version
ruby 2.6.3p62 (2019-04-16 revision 67580) [x86_64-darwin17]

$ rails --version
Rails 5.2.3

調査

準備

$ rails g model book title:string status:integer
$ rails db:migrate

enum の項目だけ定義する場合

app/models/book.rb

class Book < ApplicationRecord
  enum status: [ :nothing, :doing, :done ]
end

コンソール

irb(main):004:0> Book.statuses
=> {"nothing"=>0, "doing"=>1, "done"=>2}

-- データ作成
irb(main):005:0> Book.create(title: 'book1', status: 1)
   (0.1ms)  begin transaction
  Book Create (0.8ms)  INSERT INTO "books" ("title", "status", "created_at", "updated_at") VALUES (?, ?, ?, ?)  [["title", "book1"], ["status", 1], ["created_at", "2020-03-14 07:35:38.468498"], ["updated_at", "2020-03-14 07:35:38.468498"]]
   (1.5ms)  commit transaction
=> #<Book id: 1, title: "book1", status: "doing", created_at: "2020-03-14 07:35:38", updated_at: "2020-03-14 07:35:38">

-- データ取得
irb(main):006:0> b = Book.find(1)
  Book Load (0.2ms)  SELECT  "books".* FROM "books" WHERE "books"."id" = ? LIMIT ?  [["id", 1], ["LIMIT", 1]]
=> #<Book id: 1, title: "book1", status: "doing", created_at: "2020-03-14 07:35:38", updated_at: "2020-03-14 07:35:38">

-- stauts を更新
irb(main):007:0> b.done!
   (0.1ms)  begin transaction
  Book Update (0.6ms)  UPDATE "books" SET "status" = ?, "updated_at" = ? WHERE "books"."id" = ?  [["status", 2], ["updated_at", "2020-03-14 07:38:35.150818"], ["id", 1]]
   (0.9ms)  commit transaction
=> true

enum で key と value を定義する場合

app/models/book.rb

class Book < ApplicationRecord
  enum status: { nothing: 0, doing: 2, done: 4 }
end

コンソール

-- データ取得
irb(main):011:0> b = Book.find(1)
  Book Load (0.1ms)  SELECT  "books".* FROM "books" WHERE "books"."id" = ? LIMIT ?  [["id", 1], ["LIMIT", 1]]
=> #<Book id: 1, title: "book1", status: "doing", created_at: "2020-03-14 07:35:38", updated_at: "2020-03-14 07:38:35">
irb(main):012:0> b.status
=> "doing"

-- データ更新
irb(main):013:0> b.done!
   (0.1ms)  begin transaction
  Book Update (0.3ms)  UPDATE "books" SET "status" = ?, "updated_at" = ? WHERE "books"."id" = ?  [["status", 4], ["updated_at", "2020-03-14 07:42:16.748137"], ["id", 1]]
   (1.0ms)  commit transaction
=> true

enum をメソッドみたいに使えるの知りませんでした。

参考

ActiveRecord::Enum