Limit action query

[Hank]

I have a form based on an append query that is used to take daily work
attendance. Records are appended to a table showing who was a work on a
given day.
The problem is: the query can be run more than once per day - thus giving
more than on attenddance record for each person.

How can I limit the query to only be run once per day or limit the table to
only accept one record per employee per day?

Hope this is clear.

Thanks
Hank

 

[Hank]

Tanks for your reply.
I guess I don't fully undrstand how to set up a unique key. I do have the
primary key as the empID. I have tried changing the Unique Vaulue
properties of the query to YES, but cannot run the query at all now.
How would I set a unique key using the empID and the workdate so that an
empID can only be used once for each workday?
Thanks again
Hank