title: How to delete a deep nested object in mongodb
body: <p>Say I have a document that represents books like this:</p>
  
  <pre><code>{
     "_id":"1234567890",
     "title":"Lord Of The Rings",
     "books": {
        "1234567890":{
           "_id":"123456789890",
           "title":"The Two Towers",
           "page_count":{
              "en":6000,
              "de":7000
           }
        },
        "2234567890":{
           "_id":"223456789890",
           "title":"The Return Of The King",
           "page_count":{
              "en":6000,
              "de":7000
           }
        },
     }
  }
  </code></pre>
  
  <p>How would I go about removing the page count for the 2nd book? I tried</p>
  
  <pre><code>{$unset : {"books.2234567890.page_count":""}}
  </code></pre>
  
  <p>Didn't work. Any ideas?</p>
  
  <p>Thanks a lot</p>