ohbarye https://blog.hatena.ne.jp/ohbarye/ valid,invalid https://ohbarye.hatenablog.jp/ Ruby Ruby on Rails ActiveRecord ohbarye Advent Calendar 2020 has_many*1にblockを渡すとassociationにメソッドを追加することができる。 class User < ActiveRecord::Base has_many :posts do def stats group(:status).count # このcontextで`self`は`ActiveRecord::Associations::CollectionProxy` # `proxy_association.owner`で`user.posts`の`user`にアクセスすることもできる end end end user.posts.stats # => {'draft'=… 190 <iframe src="https://hatenablog-parts.com/embed?url=https%3A%2F%2Fohbarye.hatenablog.jp%2Fentry%2F2020%2F12%2F30%2Factive-record-association-extensions" title="ActiveRecord Association extensionsでメソッドを追加する - valid,invalid" class="embed-card embed-blogcard" scrolling="no" frameborder="0" style="display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;"></iframe> https://avatars3.githubusercontent.com/u/1811616 Hatena Blog https://hatena.blog 2020-12-30 20:34:25 rich https://ohbarye.hatenablog.jp/entry/2020/12/30/active-record-association-extensions 1.0 100%