/**
  * 
  * @param string $key
  * @return EhrlichAndreas_Db_Adapter_Abstract
  */
 public function getDbConnection($key = 'default')
 {
     $index = 'dbconnection' . $key;
     if (!EhrlichAndreas_Mvc_Registry::isRegistered($index)) {
         $config = EhrlichAndreas_Mvc_Registry::get('config');
         if (isset($config['db'][$key])) {
             $dbConfig = $config['db']['default'];
             $dbConnection = EhrlichAndreas_Db_Db::factory($dbConfig);
             EhrlichAndreas_Mvc_Registry::set($index, $dbConnection);
             return $dbConnection;
         }
     }
     return EhrlichAndreas_Mvc_Registry::get($index);
 }