Do you want to pull them up in a found set?
If so, define this calculation field set to return text:
EmployeeID & "|" & JobId & "|' & Date
Enter find mode, put a ! in this one field and perform the find. Then sort your records on this same field to group the duplicate values.
If you want to prevent the creation of such a duplicate record, use the above expression as an auto-enter calcualtion on a text field and specify a unique values validation rule for it.
Thanks, it works great.