On 7/18/08, Jason Yergeau <[EMAIL PROTECTED]> wrote: > > Hi Rob --- > > MySQL 5. > > > > On Fri, Jul 18, 2008 at 3:01 PM, Rob Wultsch <[EMAIL PROTECTED]> wrote: > > On Fri, Jul 18, 2008 at 2:00 PM, Jason Yergeau <[EMAIL PROTECTED]> > wrote: > >> I'm having trouble working through a data problem. Any tips or > >> keywords that might clue me into a known pattern would be incredibly > >> appreciated! > >> > >> I have about 500,000 users in my system. Each user has a points > >> balance, updated by a system over which I have no control. I'd like > >> to track changes to each user's point balance over time by taking > >> timestamped snapshots of their balance, and saving it into a new > >> table. > >> > >> It's easy to take the snapshot: > >> > >> insert into balances (userid, points) select userid, points from users; > >> > >> This quickly takes the points field from my users table, and saves it > >> into a balances table, which saves the data along with a timestamp. I > >> can run that query on a regular basis without overly taxing my system. > >> > >> The first time its run, I get 500,000 rows of data. That's fine. But > >> the next time I run a query, I only want to save the differences in > >> balance. > >> > >> Anyone have any tips? > >> > >> Best, > >> Jason > > > > What version of mysql do you need this to work with? >
I may be wrong, but I think you could accomplish this through the use of triggers. Triggers are designed to monitor data change activity. -jp -- Broken promises don't upset me. I just think, why did they believe me? deepthoughtsbyjackhandy.com
