SQL Server Programming - Check constraints

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Author

Check constraints

Niclas

2005-10-30, 7:57 am

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

Tony Rogerson

2005-10-30, 7:57 am

alter 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
>

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