title: Handling optional/empty data in MongoDB
body: <p>I remember reading somewhere that the mongo engine was more confortable when the entire structure of a document was already in place in case of an update, so here is the question.</p>
  
  <p>When dealing with "empty" data, for example when inserting an empty string, should I default it to <code>null</code>, <code>""</code> or not insert it at all ?</p>
  
  <pre><code>{
      _id: ObjectId("5192b6072fda974610000005"),
      description: ""
  }
  </code></pre>
  
  <p>or</p>
  
  <pre><code>{
      _id: ObjectId("5192b6072fda974610000005"),
      description: null
  }
  </code></pre>
  
  <p>or</p>
  
  <pre><code>{
      _id: ObjectId("5192b6072fda974610000005")
  }
  </code></pre>
  
  <p>You have to remember that the <code>description</code> field may or may not be filled in every document (based on user input).</p>