title: When to embed documents in Mongo DB
body: <p>I'm trying to figure out how to best design Mongo DB schemas. The Mongo DB documentation recommends relying heavily on embedded documents for improved querying, but I'm wondering if my use case actually justifies referenced documents.</p>
  
  <p>A very basic version of my current schema is basically:
  (Apologies for the psuedo-format, I'm not sure how to express Mongo schemas)</p>
  
  <pre><code>users {
    email (string)
  }
  
  games {
    user (reference user document)
    date_started (timestamp)
    date_finished (timestamp)
    mode (string)
    score: {
      total_points (integer)
      time_elapsed (integer)
    }
  }
  </code></pre>
  
  <p>Games are short (about 60 seconds long) and I expect a lot of concurrent writes to be taking place.</p>
  
  <p>At some point, I'm going to want to calculate a high score list, and possibly in a segregated fashion (e.g., high score list for a particular game.mode or date)</p>
  
  <p>Is embedded documents the best approach here? Or is this truly a problem that relations solves better? How would these use cases best be  solved in Mongo DB?</p>