title: Are Database Layout Updates still used in Magento?
body: <p>Deep in the Magento Layout system, there's the following code that's used to turn your package layout xml files into the specific XML needed to create your Blocks, and therefore create your pages</p>
  
  <pre><code>public function merge($handle)
  {
      $packageUpdatesStatus = $this-&gt;fetchPackageLayoutUpdates($handle);
      if (Mage::app()-&gt;isInstalled()) {
          $this-&gt;fetchDbLayoutUpdates($handle);
      }
  }
  </code></pre>
  
  <p>The second method there <code>fetchDbLayoutUpdates</code> tries to load additional XML Updates from the database with SQL queries something like this</p>
  
  <pre><code>SELECT `update`.`xml` FROM `core_layout_update` AS `update`
  INNER JOIN `core_layout_link` AS `link` 
      ON link.layout_update_id=update.layout_update_id 
  WHERE (link.store_id IN (0, '1')) 
      AND (link.area='frontend') 
      AND (link.package='default') 
      AND (link.theme='default') 
      AND (update.handle = 'default') 
  ORDER BY `update`.`sort_order` ASC'
  </code></pre>
  
  <p>Both the <code>core_layout_update</code> and <code>core_layout_link</code> tables are empty in a default installation.</p>
  
  <p>So, I've always assumed this is a legacy feature that predates my time with Magento.  Does anyone know if this feature is used anywhere by</p>
  
  <ol>
  <li><p>The Magento Core Codebase</p></li>
  <li><p>Any well known/prominent Extensions</p></li>
  <li><p>You!</p></li>
  </ol>
  
  <p>I can see why the feature's been left in place (legacy concerns and what not), but I'm curious if it's something that's been officially-ish abandoned, or if it's just vastly under utilized.</p>