Ruby MongoDB Driver — Ruby Driver Manual 2.8 JOIN ができないので、キャッシュでうまいことやる? Caching to Avoid N+1 When we display our list of stories, we'll need to show the name of the user who posted the story. If we were using a relational database, we could perform a join on users and stores, and get all our objects in a single query. But MongoDB does not support joins and so, at times, requires bit of denormaliz