On 13 Jun 2003 at 4:02, gamin wrote: > To each colorID you assign a unique prime number (maintain this in a > table). For each itemID now you have a unique colorPRODUCT (product of > the prime numbers coressponding the various colorIDs for this itemID). > To add a colorID to an itemID simply muliply the new prime > (coressponding to the colorID being added) to the old colorPRODUCT. In > the same way to remove a colorID devide colorPRODUCT by the > corressponding prime. And to find the itemID which has a particular > set of colors just check for the colorPRODUCT.
A more normal way, which wouldn't require such large numbers or the complication of factoring, would be to assign powers of 2 to the colors and add them rather than multiplying them. Or you could use the SET column type in MySQL, which handles the powers of 2 behind the scenes: http://www.mysql.com/doc/en/SET.html -- Keith C. Ivey <[EMAIL PROTECTED]> Tobacco Documents Online http://tobaccodocuments.org -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
