Validation dependent yes/no fields in a form

[frankatlarge]

Good morning


Thanks in advance for your assistance. I have two 'yes/no' fields displayed in a form that are dependent and I want to use a validation in the form to prevent them from both being ticked yes but what I've tried doesn't seem to be working.
The database is for school attendance and the fields are 'Full day' and 'Half day'. They can both be no, or either yes, but not both yes.

I've tried ([Full day] =-1) XOR ([Half day] =-1) but I'm obviously doing something wrong. Suggestions?

[Bob Fitz]

I would use some code in the form's Before Update event. Not tested, but something like:

If Me.[Full Day] = True AND Me.[Half Day] = True Then
  Cancel = True
  Msgbox "'Full Day' and 'Half Day' can't both be Yes"
End If

[frankatlarge]

Thanks Bob - I'll give that a go when I'm home from work tonight

I would use some code in the form's Before Update event. Not tested, but something like:

If Me.[Full Day] = True AND Me.[Half Day] = True Then
  Cancel = True
  Msgbox "'Full Day' and 'Half Day' can't both be Yes"
End If

[frankatlarge]

Thanks Bob - worked perfectly. Much appreciated.