MongoDB date index
<p>I am using node.js and mongodb for my small application and I want to index my document by date object. For Example </p>

<pre><code>var MySchema = new Schema({
    created_at: { type: Date, default: Date.now }
});

myschema.index({created_at: -1});
</code></pre>

<p>But how I understand, each object will have nearly unique create_id field. Wouldit work well ? and would this method give me effect. If you can, please also send me any articles about mongodb date indexing.</p>