Handling list items.

Question

Hi Masters
I have a requirement where in there will be two list items. The first and second list items default value has to be taken from the database for the record.
I have acheived this in post-query trigger. like take the values for the list tiems form the database and set them as default values. this is done programatically. The user has to be able to select a different value from the first list. Then a correspoding list fo values for the second list has to be retrieved from the database. after selecting the required changes the user will have to be able to submit the form where the changes get recorded in the database.
how ever i am facing the problem, as i am doing this work in post-query trigger . what ever the value i select it is not changing.
the code in the post_query looks like
if populate_group(grp_id) = 0 then
populate_list('datablock.list_item1',grp_id);
select rec_id into v_rec_id from my_table where primary_key = 1;
:datablock.list_item1 := v_rec_id ;
else
message('error ');
end if;
can you suggest a better way to implement the requirement.
Thank you very much for the answers.

Answer 1

Say you have created procedure to populate list 2
PROCEDURE populate_list2 IS
group_query varchar2(1000);
group_id RECORDGROUP ;
errorcode Number;
begin
group_id := Find_Group('MY_GROUP1');
if not id_null(group_id) then
delete_group('my_group1');
end if;
-- Here I'm assuming that datablock.list_item1 is varchar. You can make changes according to your datatype
group_query := 'SELECT a, b FROM test where b = '''||:datablock.list_item1||'''';
group_id := create_group_from_query('MY_GROUP1',group_query);
errorcode := populate_group(group_id);
if errorcode = 0 then
populate_list('datablock.list_item2',group_id);
else
message('Error populating group '||errorcode);
end if;
end;
Now in Post-Query you have following code :
-- Code to populate first list item
if populate_group(grp_id) = 0 then
populate_list('datablock.list_item1',grp_id);
select rec_id into v_rec_id from my_table where primary_key = 1;
:datablock.list_item1 := v_rec_id ;
else
message('error ');
end if;
-- Code to populate second list item
If :datablock.list_item1 Is Not Null
Populate_list2;
End If;
This way your second list will be populated.
Now in the When-List-Changed trigger of datablock.list_item write
--Code to populate second list item
Populate_list2.
This will re-populate the list2 when you change the selection in List1.
Hope this helps.