RE: [PHP] Dear Lazy Web: Pseudo Randomisation Strategies on Listing Websites

Hi Col, Interesting problem. > Are there any other approaches I've missed? Off the top of my head, how about this: 1. Add a new unsigned int column called "SortOrder" to the table of widgets or whatever it is you're listing 2. Fill this column with randomly-generated numbers between 0 and whatever the unsigned int max is (can't remember exactly but 4.2 billion ish) 3. Add the SortOrder column to the end of all your ORDER BY clauses - SELECT foo ORDER BY TypeOfListing, SortOrder will give you widgets sorted by Gold/Silver/Bronze type, but in a random order for each type 4. Every hour/day/week/whatever, update this column with different random numbers Advantages: practically no hassle/overhead/maintenance for you; provides same ordering sequence for all users at the same time; only breaks "third one down"-type references when you refresh the SortOrder column rather than on each session or page view; reasonably proxy- and cache-friendly especially if you send a meaningful HTTP Expires header. Disadvantages: breaks user persistence if they visit before and after a SortOrder refresh ("I'm sure the one I wanted was at the top of the list yesterday..."); more effort to demonstrate randomness to the client ("OK, see how you're in ninety-third place today? Well, check again tomorrow and you should be somewhere else on the list"). Hopefully food for thought anyway. Cheers Jon