Apex Application Parent Tabs

Question

Request for other peoples experience with problems using the apex_application_parent_tabs view. We have solved the problem that follows, but are interested in finding out other peoples solutions to this problem.
We have used the following dynamic tree to create a navigation menu within an application:-
select id, pid,
case when :FLOW_STEP_ID = page_no then '<div class="osl_breadcrumb">'||name||'</div>' else '<div class="osl_breadcrumb">'||name||'</div>' end name,
case when navigation = 'Y' then 'f?p='||x.flow_id||':'||page_no||':&SESSION.::NO::P0_PARENT_TAB:'||parent_tab||''
else null
end link,
null a1, null a2
from ( select id, pid, name, navigation, parent_tab, display_seq, flow_id, page_no
from (select distinct a.CURRENT_FOR_TABSET id,
case when length(a.component_comment) = 4
then (select z.CURRENT_FOR_TABSET from apex_030200.APEX_APPLICATION_PARENT_TABS
z where z.component_comment = substr(a.component_comment, 0, 3))
else a.TAB_SET
end pid,
a.TAB_LABEL name, 'N' navigation, 'PT' parent_tab, a.DISPLAY_SEQUENCE display_seq,
a.APPLICATION_ID flow_id, 0 page_no
from apex_030200.APEX_APPLICATION_PARENT_TABS a
where a.application_id = v('app_id')
union all
select distinct b.TAB_NAME id, b.TAB_SET pid, b.TAB_LABEL name, 'Y' navigation,
(select c.TAB_COMMENT
from apex_030200.WWV_FLOW_TOPLEVEL_TABS c
where c.CURRENT_ON_TABSET = b.TAB_SET
and c.FLOW_ID= b.APPLICATION_ID) parent_tab,
b.DISPLAY_SEQUENCE display_seq, b.APPLICATION_ID flow_id, b.TAB_PAGE page_no
from apex_030200.APEX_APPLICATION_TABS b
where b.application_id = v('app_id')) comp,
osl.ap_stu_portal_activated flag
where comp.id=flag.ID_value
and flag.ACTIVE='Y'
order by comp.display_seq
) x
This works OK in Apex 3.2 against an Oracle 11.1.0.6 database but will not run against an 11.1.0.7 database. However, if the sql is run manually in e.g. SQLDeveloper against 11.1.0.7, then it runs without a problem (substituting in valid values as appropriate). There is no debug output at the point the tree statement woudl run when the application is run in debug mode. The monitoring tools do not show any expensive cpu or any particular run away query - and don't show this tree statement being run.
We think Apex is trying to rewrite the sql, but as the underlieing apex view is a complicated series of nested case statements as well, we think the resultant sql is somehow flawed.
We have resolved the issue by creating a view:-
create or replace view osl.ap_portal_menu_tree as
select id, pid, name, navigation, parent_tab, display_seq, flow_id, page_no from (
select distinct a.CURRENT_FOR_TABSET id,
case when length(a.component_comment) = 4 then (select z.CURRENT_FOR_TABSET from apex_030200.APEX_APPLICATION_PARENT_TABS
z where z.component_comment = substr(a.component_comment, 0, 3)) else a.TAB_SET end pid,
a.TAB_LABEL name,
'N' navigation,
'PT' parent_tab,
a.DISPLAY_SEQUENCE display_seq,
a.APPLICATION_ID flow_id,
0 page_no
from
apex_030200.APEX_APPLICATION_PARENT_TABS a
union all
select distinct b.TAB_NAME id,
b.TAB_SET pid,
b.TAB_LABEL name,
'Y' navigation,
(select c.TAB_COMMENT from apex_030200.WWV_FLOW_TOPLEVEL_TABS c where c.CURRENT_ON_TABSET = b.TAB_SET and c.FLOW_ID= b.APPLICATION_ID) parent_tab,
b.DISPLAY_SEQUENCE display_seq,
b.APPLICATION_ID flow_id,
b.TAB_PAGE page_no
from apex_030200.APEX_APPLICATION_TABS b)
comp, ap_stu_portal_activated flag
where comp.id=flag.ID_value and flag.ACTIVE='Y'
The tree has then been re written as:-
select id,
pid,
case when :FLOW_STEP_ID = page_no then '<div class="osl_breadcrumb">'||name||'</div>' else '<div class="osl_breadcrumb">'||name||'</div>' end name,
case when navigation = 'Y' then 'f?p='||x.flow_id||':'||page_no||':&SESSION.::NO::P0_PARENT_TAB:'||parent_tab||'' else null end link,
null a1,
null a2
from osl.ap_portal_menu_tree x
where x.flow_id = v('app_id')
order by x.display_seq
This works perfectly, suggesting that the problem may be how Apex’s sql engine runs the nested case statements.
Any similar experiences?
Thanks
Occam

Answer 1

Dear Prabodh,
Thank you for you response.
Only I need a list for the second level tabs since I have the first level on the top navigation area of my page template
As I understood, I wrote the following code for the list
SELECT null,
       TABLABEL label,
       'f?p=&APP_ID.:' || TABPAGE || ':'||:APP_SESSION||':::::' target,
       (CASE 
            WHEN TABPAGE = :APP_PAGE_ID THEN 'YES'
            ELSE 'NO' END) is_current
from MY_VW_TABS
WHERE PTTABNAME in (select TAB_SET from APEX_APPLICATION_TABS where TAB_PAGE = :APP_PAGE_ID)In page 0, I created a list region with template (Vertical Unordered List without Bullets), however, it is not displaying anything!!
What is missing to get list displayed?
Best Regards
Mahmoud