Thanks for your reply, now I know where to put the code.
I noticed in your code snippet, you are setting the key the hard way. I use a stored procedure as the default value for my primary keys

function new_key
parameters tbl_name, key_field
private newkey
select max(&key_field) from &tbl_name into array temp
if _tally >0 && found records
newkey = temp(1)+1
else && empty table
newkey = 1
endif
return newkey

then in the key field's default value I put new_key("sometbl","keyfield")
and I never worry about unique keys