Check constraints

Hi,
If I have three columns called 'userid' 'event' and 'result' and only allow
one result row per event and userID. I.e. each user can only have one result
per event.
How would a constraint expression look like for this ?
Nicalter table <yourtable> add constraint uk_<yourtable>_event_userid unique
( event, userid )
That will only allow one row to have the same event and userid.
Tony.
Tony Rogerson
SQL Server MVP
http://sqlserverfaq.com - free video tutorials
"Niclas" <lindblom_niclas@.hotmail.com> wrote in message
news:edSyoJV3FHA.3292@.tk2msftngp13.phx.gbl...
> Hi,
> If I have three columns called 'userid' 'event' and 'result' and only
> allow one result row per event and userID. I.e. each user can only have
> one result per event.
> How would a constraint expression look like for this ?
> Nic
>