title: Update Object at Specific Array Index in MongoDB
body: <p>I have a collection of the form</p>
  
  <pre><code>{ id : 1,
    data: [ [ { name : "alice" }, { name : "bob" } ],
            [ { name : "dan" },   { name : "rob" } ] ] }
  </code></pre>
  
  <p>and the structure of the array has meaning. How would I update the first element ([0][0]) and set name = "alex". I've seen many questions addressing how to update array elements that match a query but not specific elements. To be clear, after the update, the record should look like this:</p>
  
  <pre><code>{ id : 1,
    data: [ [ { name : "alex" },  { name : "bob" } ],
            [ { name : "dan" },   { name : "rob" } ] ] }
  </code></pre>