title: Query data on firebase for web
body: <p>So I'm building a music platform, using firebase, where users can upload their songs. When a user logs in, I save their data on the "usuarios" node. And when they upload a song, I push to the "musicas" node (child of usuarios). 
  This way, I know who uploaded the song. </p>
  
  <p>But the problem is: I want to get a list of all the last 15 songs uploaded. How do I do that? Did I structure my data wrong?</p>
  
  <p>Here's what I tried:</p>
  
  <pre><code>  var musicsRef = firebase.database().ref('usuarios').orderByChild('musicas');
    musicsRef.on('value', function(snapshot) {
    console.log(snapshot.child('musicas');
  });
  </code></pre>
  
  <p>Here's my database structured:<a href="https://i.stack.imgur.com/2SQLl.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/2SQLl.png" alt="enter image description here"></a></p>