Form - Insert only if not a duplicate

Question

Hi,
In Oracle Portal I have a form that submit data to a table.
I only want the information to be inserted if the table doesn't already contain that email address that the user has types into the form.
In the additional PL/SQL code I added the following under 'before processing the form'
declare
form_email varchar2(80);
row_count number;
begin
form_email := p_session.get_value_as_varchar2(
p_block_name => 'DEFAULT',
p_attribute_name => 'A_EMAIL');
select count(*) into row_count
from schema.mytable
where upper(email) = upper(form_email);
if row_count > 0 then
htp.p('You have already submitted the form');
end if;
end;
The above did nothing at all. The record was still inserted. I tried just having the htp.p('You have already submitted the form'); in there just to see if it displayed, but it doesn't seem to be processing anything at all.
I tried putting the code in the 'after processing the form' section, but this failed to process anything either.
I've even tried putting the code on the 'Submit' button's PL/SQL Button Event Handler, but again, nothing happened.
What am I doing wrong?
Thanks.

Answer 1

Sugestion:
1. Create a unique Constraint on the EMAIL column.
2. In the form design page, at the INSERT button Event Handler (PL/SQL), enter a code which intercepts the exception:
exception
when DUP_VAL_ON_INDEX then
htp.p('already exists');
If you have access to metalink , cf note [cf note 139274.1|https://metalink.oracle.com/CSP/ui/flash.html#tab=KBHome(page=KBHome&id=()),(page=KBNavigator&id=(bmDocType=HOWTO&bmDocDsrc=KB&bmDocTitle=%3Cb%3Eforms%3C/b%3E%20insert,%20update%20and%20delete%20PL/SQL%20event%20handler:%20user%20friendly%20%3Cb%3Eerror%3C/b%3E%20screen&bmDocID=139274.1&viewingMode=1143&from=BOOKMARK))].
Patrick.