Whats the best way to check table before form deletion or update ?

Question

Hi, I have a func_staff table made up of a composite key - func_no and staff_id. I have a form where the datablock references this table.
I need to be able to check that before a func_no and staff_id combination on the form are written to the database that that combination does not already exist in the table.
What would be the code for that ? I've tried stuff like IF EXIST statements and even a select statement but I totally worded it it wrongly.
To DELETE an entry in that same table, would the best way to be create an LOV for both func_no and staff_id, the problem with that would be if a user selected a combination that does not exist ? Could I create a combined LOV that would populate each field ?? (this way I could be 100% sure that the selected combination is valid)
Thanks Peeps.

Answer 1

hi,
you can try and use the count(*), before deleting and updating
lets say
select count(*)
into l_count
from table_name
where column1 = :block.column1
and column2 = :block.column2;
if l_count <> 1
then
insert into..........
else
show error message;
raise form trigger failure;
end if;
similarly u can use l_count before deleting.
regards,
Mayank