class ArticlePage extends Page
{
   static $db = array(
             'Date'=>'Date',
             'Author'=>'Text'
          );
}

class ArticlePage_Controller extends Page_Controller
{
   public function getCMSFields()
   {
      $fields = parent::getCMSFields();
      
      $dateField = new DateField('Date');
      $dateField = setConfig('showcalendar', true);
      $fields->addFieldToTab('Root.Main', $dateField, 'Content');
      $fields->addFieldToTab('Root.Main', new TextField('Author'), 'Content');
      
      return $fields;
   }
}