title: Does not contain _id or shard key for pattern {_id:hashed}
body: <pre><code>db.books.update({bookId:"123461"},{$set:{"bookPrice":"6.23"}})
  </code></pre>
  
  <p>I get the error:</p>
  
  <pre><code>   update { q: { bookId: "123461" }, u: { $set: { bookPrice: "6.23" } }, multi: false, upsert: false } does not contain _id or shard key for pattern { _id: "hashed" }
  </code></pre>
  
  <p>But when I use below it works.</p>
  
  <pre><code> db.books.update({_id:ObjectId("54b88167498ec382221a82c2")},{$set:     {"bookPrice":"6.23"}})
  </code></pre>
  
  <p>Why doesn't it work with the bookId</p>