Using a LOV for the Start of a Tree - Pblms using LOV value for Start SQL

Question

I'm trying out my first APEX Tree using P20 and am having problems with it. The data structure is I have a clients table, an users table, a plans table and a union table (plan_users) that shows which users for a client are working on plans. An user belongs to a client and can be assigned to plans (plan_users).
client_id (key to clients table and part of the composite key for users, plans and plan_users) is available as an application item which I can reference as :FOCUS_CLIENT_ID.
I created several LOV's in the Shared Components. The PLANS_LOV returns all plans defined for the :FOCUS_CLIENT_ID. I've referenced this PLANS_LOV in the P20_ROOT_TREE which is setup to display the list of Plans for the Client as a SELECT LIST WITH SUBMIT. That seems to work and I can select the Plan.
I then modified the SOURCE for the P20_ROOT_TREE to add a select statement to take the PLANS_ID selected in the LOV and use it in a Select to bring up the owner of the plan as the starting user for the tree. This is where I get an error when executing the SOURCE select statement which looks like this:
select p.user_id id, p.plan_owner_id pid, u.user_lname name, null link
from plan_users p, users u
where p.client_id = :FOCUS_PLAN_ID and p.PLAN_ID = :PLANS_LOV
and p.user_id = p.plan_owner_id
and u.client_id = :FOCUS_PLAN_ID and u.user_id = p.user_id
I'm guessing that the problem is what I'm referencing as :PLANS_LOV in the statement below. However I cannot find any information on how to reference the returned value from the PLANS_LOV for Page 20 so I've tried this.
If this works right, then I want the user to select a PLAN from the LOV box and then see a tree displayed with all USERS hierarchically displayed beneath the Plan Owner. There may be multiple levels of users display under the Plan Owner.
Here's the DEBUG page error I get. The number 4 is the correct Plan # I want to select Users for. The title on the page is "Available Plans". - Select Plan - is the default Null Value and Test Plan One is the Plan (#4) that I selected.
Item: P20_TREE_ROOT COMBOBOX_WITH_SUBMIT
Available Plans
-Select Plan -Test Plan One
[javascript:popupURL('f?p=4000:371:1020131294804981::::P371_ID,FB_FLOW_ID,FB_FLOW_PAGE_ID:1096326828951548,101,20');|Edit]Warning: Tree root ID "4" not found.
0.05: Computation point: AFTER_BOX_BODY 0.05:
Processing point: AFTER_BOX_BODY
The query I'm using for populating the rest of the tree after the START is this statement below, but I don't think I'm getting to this point yet.
select p.user_id id, p.plan_owner_id pid, u.user_lname name, null link, null a1, null a2
from plan_users p, users u
where p.client_id = :FOCUS_CLIENT_ID
and u.client_id = :focus_client_id
and u.user_id = p.client_id
order by name
I haven't been able to find any examples of someone using a LOV as part of the START definition for a Tree. All of the examples I've seen use a fixed value (i.e. 1).
Anyone have some ideas?
Thanks!
Rob

Answer 1

Hi,
Try something like:
select p.user_id id, p.plan_owner_id pid, u.user_lname name, null link, null a1, null a2
from plan_users p, users u
where p.client_id = :FOCUS_CLIENT_ID
and u.client_id = :focus_client_id
and u.user_id = p.client_id
START WITH :FIRST_USER_ID
CONNECT BY PRIOR p.user_id = p.plan_owner_id
order by name:FIRST_USER_ID should be computed to be the first p.user_id value that matches the filter. Ideally, the p.plan_owner_id value should be null for this user as this user should identify the top of the tree. As an example, the following, using the EMP table, will allow you to display a tree with any manager as the root:
SELECT
EMPNO ID,
ENAME NAME,
CASE WHEN EMPNO = :P1_EMPNO THEN NULL ELSE MGR END PID,
null LINK,
null a1,
null a2
FROM EMP
START WITH EMPNO = :P1_EMPNO
CONNECT BY PRIOR EMPNO = MGRAndy