title: How to convert QString to QDate in specific format?
body: <p>I have a <code>QDateEdit</code> in my GUI from which I convert the <code>QDate</code> to <code>QString</code> and add it to my database. The <code>QString</code> date is saved in the database in this format: 20/12/2015.</p>
  
  <p>In case a user want to edit the date, then I need to show the date on the <code>QDateEdit</code> field on the GUI again. Hence, I need to fetch the database, bring back the date (which is in <code>QString</code> format) and convert it to <code>QDate</code> back again in order to put it on the <code>QDateEdit</code> field on the GUI.</p>
  
  <p>However, I cannot manage to convert that <code>QString</code> format (i.e.: 20/12/2015) to <code>QDate</code> using the following:</p>
  
  <pre><code>QString date_string_on_db = "20/12/2015";
  QDate Date;
  Date.fromString(date_string_on_db,"dd/MM/YYYY");
  </code></pre>
  
  <p>The <code>Date</code> is always returning <code>invalid</code>.</p>
  
  <p>what should I do ?</p>