title: Firebase security rules to check unique value of a child #AskFirebase
body: <p><a href="https://i.stack.imgur.com/6PhTf.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/6PhTf.png" alt="enter image description here"></a></p>
  
  <p>The structure of my firebase database is as shown above. How do I ensure the urls are unique and there are no duplicates? Since, these are urls I cannot use them directly as paths, I am forced to use them as values. So solutions like <a href="https://stackoverflow.com/a/25328654">this</a> won't work.</p>