removing an object from a mongodb document
<p>I have a document in <code>Mongodb</code> collection, where I want to <code>remove an object</code>, using <code>title</code> key. </p>

<p>I tried using <code>$unset</code>, but it only <code>removes the title key</code> not the object to which it belongs.</p>

<pre><code>{
    "_id" : ObjectId("576b63d49d20504c1360f688"),
    "books" : [
        {
            "art_id" : ObjectId("574e68e5ac9fbac82489b689"),
            "title" :"abc",
            "price" : 40
        },
        {
            "art_id" : ObjectId("575f9badada0500d192c53f4"),
            "title" : "xyz",
            "price" : 20
        },
        {
            "art_id" : ObjectId("57458224d86b3d1561150f17"),
            "title" : "def",,
            "price" : 30
        }
    ],
    "user_id" : "575570c315e27d13167dfc0d"
}
</code></pre>