shopping cart - how to avoid orphaned carts

[sneakyimp]

howdy:

i'm building a simple shopping cart. i was planning to use the session ID to link shopping carts to a database table containing cart contents. There is no real danger of users sharing important info (i.e, credit card data) because i won't be collecting any.

HOWEVER, i was wondering how i should go about purging abandoned shopping carts...perhaps delete all old shopping carts when a new shopping cart is created (based on a "last accessed" date or something)??? anybody have experience with this?

[devinemke]

i generally don't bother storing the cart contents in the database. i just store it in the session and if a cart is abandoned then i let PHP's built in garbage collecor clean things up.

if you do want to store your cart in the db then you could easily write you own garbageman routine. i would suggest storing the session ID in the db record as well as a timestamp field which (in mySQL) is automatically updated to the current time during each INSERT/UPDATE. you could then run an hourly cron to poll the database for old timestamps and delete.