/* base class constructor */
	function DBAccess( $unique_id = null )
	{
		$last_error_code = 0;
		$last_sql_error = 0;
		
		if( $unique_id == null )
		{
			/* generate a new transaction, with no data */
		} else {
			this->retreiveData(); /* load the transaction from the database, or return an error code */
		}
	}

	/* fill data with data from DB -- must be supplied in child class */
	function retreiveData();