Dlookup

[IKZOUHETNIETWETEN]

By adding an unit number A1 and an OUT date in the form, i want to get a message that an error/popup message that its already OUT (and so cant be added in the table). (Because unitnumber A1 is already in the table as A1 with an OUT date)


Table name: Units
Form name: Units
field1 = Unit_name
field2= In_date
field3= Out_date
field4 = Project_name

This is what I have so far:

Private Sub Unit_name_BeforeUpdate(Cancel As Integer)
DLookUp("Units", "[Unit_name]= " & [Unit_name] & " And [Date_out]= '" & [Date_out] & "'")
  MsgBox "Name Is Already In Database!"
End If
End Sub

[pbaldy]

This should help:

http://access.mvps.org/access/general/gen0018.htm

also, you can't use the DLookup() like that. I'd use DCount() and test for greater than zero.