rails - active record : distinct

👆 schema

 genre = Genre.first
      expect(genre).to respond_to :albums
      expect(genre.albums.size).to eq 117
      # 같은 장르 앨범만 보여주기
      expect(genre.albums.last.title).to eq "Every Kind of Light"
      # 같은 장르의 아티스트만 보여주기 + 마지막 타이틀. 

정리 🔥

• Use the distinct method to keep the collection free of duplicates.
• Show only one Article, because the collection loads only unique records
• through랑 같이 많이 쓰임

  has_many :albums, -> {distinct}, through: :tracks