Check if htmldb_item is displayed or not

Question

Morning guys,
I created a manual tabulat form but some of the Items are only displayed when there is a request to display them. The problem is, when they are not displayed, the code to update the corresponding database table is not executed, I get an error message.
Now my question:
Does anybody know if it is possible to include a piece of code in the following code to check wether apex_application.g_f11(z) is found or not. If it is not found the code in the loop should not be executed:
  for z in apex_application.g_f11.first..apex_application.g_f11.last loop
    if apex_application.g_f11(z) is not null then
    insert into zf_asn_supplier (suppl_name, suppl_number, contact, email, ordering_address,
    area, sap_plant) VALUES               (apex_application.g_f11(z),
                                           apex_application.g_f12(z),
                                           apex_application.g_f13(z),
                                           apex_application.g_f14(z),
                                           apex_application.g_f15(z),
                                           apex_application.g_f16(z),
                                           apex_application.g_f17(z));
    END IF;
  END LOOP;Thanks for your time and help!!!
Regards Patrick

Answer 1

Thanks for your help varad, but there is still the error message
ORA-06502: PL/SQL: numeric or value error
Perhaps a bit more information about the problem:
I have a SQL report as a manual tabular form and if there are made any changes, the database gets updated (see code below). Now I created another manual tabular form for inserting new data, which containes only one row and is empty (from dual) and which is only displayed when I send a request (Add_Row) through a button.
I know that I can also do that with a UNION ALL statement in my SQL query, but then the empty row is displayed at the end and the bottom of the report, and I want the empty row to be displayed at the top of the table.
If the empty row is displayed, the PLSQL Code works without problems, but when it's not displayed, I get the described error message.
begin
  for i in apex_application.g_f02.first..apex_application.g_f02.last loop
    merge into zf_asn_supplier dest
    using (
select
apex_application.g_f02(i) suppl_name,
apex_application.g_f03(i) suppl_number,
apex_application.g_f04(i) contact,
apex_application.g_f06(i) ordering_address,
apex_application.g_f07(i) area,
apex_application.g_f08(i) sap_plant,
apex_application.g_f09(i) supplier_id
from dual) src
on ( src.supplier_id = dest.supplier_id)
    when matched then update set
              dest.suppl_name = src.suppl_name,
              dest.suppl_number = src.suppl_number,
              dest.contact = src.contact, 
              dest.ordering_address = src.ordering_address,
              dest.area = src.area,
              dest.sap_plant = src.sap_plant
              where src.suppl_name IS NOT NULL and src.suppl_number IS NOT NULL
    when not matched then insert (suppl_name, suppl_number, contact, ordering_address, area, sap_plant)
              values (src.suppl_name, src.suppl_number, src.contact, src.ordering_address, src.area, src.sap_plant)
              where src.suppl_name is not null and src.suppl_number is not NULL;
  end loop;
  for z in apex_application.g_f11.first..apex_application.g_f11.last loop
    if apex_application.g_f11.exists(z) and apex_application.g_f11(z) IS NOT NULL then
    insert into zf_asn_supplier (suppl_name, suppl_number, contact, email, ordering_address,
    area, sap_plant) VALUES             
                                          (apex_application.g_f11(z),
                                           apex_application.g_f12(z),
                                           apex_application.g_f13(z),
                                           apex_application.g_f14(z),
                                           apex_application.g_f15(z),
                                           apex_application.g_f16(z),
                                           apex_application.g_f17(z));
END IF;
  END LOOP;