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DBに接続しているクラスの一覧を取得する

Rails4以前では結構面倒だったけど、Rails5以降では
ApplicationRecord.descendants でDBに接続しているモデルの一覧取得できる

例えばこんな感じ

model_list = ApplicationRecord.descendants

# クラス名の一覧を出力したいときはこう
model_list.map { |v| v.to_s }
=> ["User", "Owner", "Blogs::Comment"]

利用シーン

  • バッチ処理
  • xxxというメソッドが実行できるメソッドを探す場合
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