/**
* Constructor
*
* @param db $db
* @param int $timer Current time in UNIX format
* @param array $tables
* @param string $db_table_prefix
*/
public function __construct(db &$db, &$timer, array $tables, $db_table_prefix = '')
{
if (is_object($db)) {
$this->db =& $db;
}
parent::__construct($tables, $db_table_prefix, $timer);
}