Check If The Data Already Exist

Hi,

I put a Dlookup function to compare the new entry in a form and the code is like this:

If (Not IsNull(DLookup("[empno]", "Attnd_tbl" , "[empno]=[empnotxt]")))then
MsgBox "This Employee Already Exists"
cancel = true
Me!empnotxt.undo
end if
end sub

this works for comparing one field only, since I want to check if the employee is already entered on a certain date, how do I put two fields in this function to be looked up if for example "[empno]and[date]","Attnd_tbl","[empno]and[date]=[empnotxt]and[datetxt]"