/**
  * Get Module version from DB
  *
  * @param   string $moduleName
  * @return  string
  */
 function getDbVersion($resName)
 {
     if (!$this->_read) {
         return false;
     }
     if (is_null(self::$_versions)) {
         // if Core module not instaled
         try {
             $select = $this->_read->select()->from($this->_resTable, array('code', 'version'));
             self::$_versions = $this->_read->fetchPairs($select);
         } catch (Exception $e) {
             self::$_versions = array();
         }
     }
     return isset(self::$_versions[$resName]) ? self::$_versions[$resName] : false;
 }