on 5/5/05 2:52 AM, Jigal van Hemert at [EMAIL PROTECTED] wrote: > ----- Original Message ----- > From: "Scott Haneda" >> on 5/5/05 2:11 AM, Joerg Bruehe at [EMAIL PROTECTED] wrote: >> Basically, I have a chopping cart, this one is a little weird, for reasons >> not worth explaining, you have a cart when a user is not logged in, and > they >> *may* have one they made at some point when logged in. There is a chance >> the logged in cart already has stuff in the non logged in cart, I don't > want >> duplicate items in the cart, so I want to just get rid of the oldest one. > > I'd add a UNIQUE index on user id and product id (beware of the handling of > NULL values!) and use REPLACE to add the new data. > "REPLACE works exactly like INSERT, except that if an old record in the > table has the same value as a new record for a PRIMARY KEY or a UNIQUE > index, the old record is deleted before the new record is inserted." > http://dev.mysql.com/doc/mysql/en/replace.html
Cant, at least not how this mess of a site has to work. If a user is not logged in, there has to be the ability to add to a cart, all I have is a session id from the cookie, they are not logged in. so these are inserts into a cart table. Sure, I can prevent the duplicates for that session, but there comes a point where they log in. While the chances are slim, when they login, there may be a existing cart already in place for that user. So I am not inserting anything at that point, but updating old logged in cart items to the non logged in new ones. Its just a setting of the user_id in a update statement where session is either old or new. This collects the records to the users account, but, there is that rare case where they may have ended up with 2 of the same product in the cart. -- ------------------------------------------------------------- Scott Haneda Tel: 415.898.2602 <http://www.newgeo.com> Novato, CA U.S.A. -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
