If you've already got a database table with a column that holds the absolute path (or you can create one), and all you want to do is pick a number for each row, then, assuming you've marked the column that holds the number as UNIQUE, then you could just pick a random number for each row, right? Or, if you haven't filled the table yet, maybe you're looking for a feature like AUTO_INCREMENT? (a similar feature exists in virtually all databases)