title: When to use $sth->fetchrow_hashref, $sth->fetchrow_arrayref and $sth->fetchrow_array?
body: <p>I know that:</p>
  
  <ul>
  <li><code>$sth-&gt;fetchrow_hashref</code> returns a hashref of the fetched row from database,</li>
  <li><code>$sth-&gt;fetchrow_arrayref</code> returns an arrayref of the fetched row from database, and</li>
  <li><code>$sth-&gt;fetchrow_array</code> returns an array of the fetched row from database.</li>
  </ul>
  
  <p>But I want to know best practices about these. When should we use fetchrow_hashref and when should we use fetchrow_arrayref and when should we use fetchrow_array?</p>