Navigate from tree selection to parameterized report on same page

Question

I have a simple tree showing the departments and roles within our organization.
I have a simple report showing the skills required for each node in the tree, sometimes general skills that apply to whole department, sometimes specialized skills for the roles within a department.
I've created a page that has two regions. I managed to get the tree on the left and report on the right by including the two regions in the same display point and changing the column of the report to "2".
When I click a node in the tree, I want the ID behind the selection to be passed to the simple report. The report will show the skills mapped to the selected node in the tree.
But since the report is on the same page, I imagine this might be a bit tricky. When the user clicks a node, the whole page would have to be refreshed, preserving the tree expanded to the point where the user clicked, and running the report with the now filled ID.
In order to do this, I guessed I'd need an application item that preserved state. I created item F1000_OU_ID.
The SQL for the tree is :
select "OU_ID" id,
"PARENT_OU_ID" pid,
"OU_NM" name,
'f?p=&APP_ID.:1:&SESSION.::NO::F1000_OU_ID:'||"OU_ID" link,
null a1,
null a2
from "#OWNER#"."TR_OU"
order by seq_num
The SQL for the report is:
SELECT s.skill_type,
s.skill_nm
FROM tr_skill s,
tr_ou_skill os
WHERE s.skill_id = os.skill_id
AND os.ou_id = :F1000_OU_ID
Under the report region, I gave it a conditional display directive to not display until F1000_OU_ID was not null.
That's as far as I've gotten. The page runs. The regions display where I want them. But when I click nodes in the tree, the page blinks and nothing happens to the report. What am I missing Aces?
bc

Answer 1

200 views and 1 reply? Come, come, Aces, you can do better than that!
Leo, thanks for taking the time to look at it. As I understand it, the "bind" or "host variable" syntax of preceding colon, e.g. ":F1000_OU_ID" is used when referring to application or page items from a SQL Query. The "substitution" syntax of preceding ampersand and following period, e.g. "&F1000_OU_ID." is used when referring to application or page items from things like HTML text.
To verify this, I used one of the blank pages in my app, page 5. I created two regions, one HTML text, one a report based on a SQL Query.
For the HTML text, I typed in
Here is the application item value &F1000_OU_ID..
For the report's SQL query, I typed in
SELECT 'OU_ID selected is ['||:F1000_OU_ID||']' text
FROM dual
These both work as expected. After I have clicked on a node in Page 1's tree, the F1000_OU_ID is set to a value and that value then appears on page 5 in the two test regions mentioned above.
So I have no trouble passing stateful values between different pages. My problem, perhaps poorly worded in the original post, is how to "pass" the selected value to the same page, since clicking a link in the tree refreshes the page it is on, in order to pass the value to the report region on the same page.
If anyone has done this before, please chip in or point me to the thread. Various searches in the forum were just coming up with too many non-relevant results, so I thought I'd ask the experts. Thanks in advance!
bc