title: Doctrine DBAL 2: fetchAll() unnecessary array dimensions
body: <p>In doctrine DBAL2 when I execute a query like this:</p>
  
  <pre><code>&lt;?php
  $connection = $this-&gt;getDatabaseConnection();
  
  $sql =  "SELECT page_url
             FROM cms_user_page
            WHERE site_id = :siteid
              AND active = '1'
      ";
  
  $stmt = $connection-&gt;prepare($sql);
  $stmt-&gt;bindValue("siteid", $id);
  $stmt-&gt;execute(); 
  
  return $stmt-&gt;fetchAll();
  ?&gt;
  </code></pre>
  
  <p>I get a result like this:</p>
  
  <pre><code>Array
  (
      [0] =&gt; Array
          (
              [page_url] =&gt; index.php?action=login
          )
  
      [1] =&gt; Array
          (
              [page_url] =&gt; index.php?action=shoppingcart
          )
  
      [2] =&gt; Array
          (
              [page_url] =&gt; index.php?action=products
          )
  )
  </code></pre>
  
  <h3>My question is, is there a fetch mode that produces an result like this:</h3>
  
  <pre><code>Array
  (
      [0] =&gt; index.php?action=login
  
      [1] =&gt; index.php?action=shoppingcart
  
      [2] =&gt; index.php?action=products
  )
  </code></pre>
  
  <p>I could not find any info about fetch modes in the documentation. and i could do an array map. But thats overhead in my opinion..</p>