oracle apex shuttle saving deselections - oracle

Question

I'm using Apex 4.2.4 and Oracle 11g. I have a mailing list application where I'm maintaining multiple mailing lists. A given recipient may belong to one or more lists. I'm using an Apex Shuttle to maintain the lists.
The source of all mailing recipients is in the table: mail_recipient. There are four important fields in mail_recipient:
prim_key
first_name
last_name
email_address
There is another table that stores the selected recipients for a given mailing list: mail_recipient_category: The important fields in mail_recipient_category are:
prim_key
recipient_fkey (this stores the prim_key from the mail_recipient table)
category
merge_check
There are two displayed items on the page. The category drop down list (P31_email_list) and the shuttle (P31_email_list_assignments)
The LOV for P31_email_list_assignments is:
Select last_name || ', ' || first_name || ' -- ' || email_address, prim_key from mail_recipient
order by 1;
The PL/SQL function body for the shuttle source is:
declare
emp_list apex_application_global.vc_arr2;
i number := 1;
begin
for r in (Select mr.last_name || ', ' || mr.first_name || ' -- ' || mr.email_address, mr.prim_key
From mail_recipient mr left outer join
mail_recipient_category mrc
On mr.prim_key = mrc.recipient_fkey
Where mrc.category = :P31_EMAIL_LIST)
loop
emp_list(i) := r.prim_key;
i := i + 1;
end loop;
return APEX_UTIL.TABLE_TO_STRING(emp_list, ':');
end;
There is also a single page process to update the database table mail_recipient_category. The process is executed on submit after computations and validations.
Begin
MERGE INTO MAIL_RECIPIENT_CATEGORY ss
USING (
Select
shuttle.column_value shuttle_st
, db.recipient_fkey db_st
from
table(string_to_coll(:P31_email_list_assignments)) shuttle
left outer join mail_recipient_category db
on shuttle.column_value = db.recipient_fkey
and db.category = :P31_email_list) t
on (ss.recipient_fkey = t.db_st
and ss.category = :P31_email_list
)
when matched
then
update
set
ss.merge_check = ss.merge_check
delete
where
t.shuttle_st is null and ss.category = :P31_email_list
-- t.shuttle_st is null
when not matched
then
insert
(recipient_fkey, category)
values
(t.shuttle_st, :P31_email_list);
end;
The shuttle works fine to load from left to right and save items. The problem I'm having is deselecting items from the right side to the left side of the shuttle. After moving a a mail recipient from the right to the left side, when I press the submit button, the items don't leave the right side of the shuttle and the process doesn't delete the row from the mail_recipient_category table.
Thanks for your help with this.

Answer 1

After working with a very experienced colleague, we determined that the page process was at fault. Specifically, the Delete clause of the Merge statement doesn't seem to work for this shuttle. We ended up adding a separate Delete statement after the the Merge statement in the page process.
I also dropped the mail_recipient_category table and am now using the more meaningful name mail_recipient_list.
The shuttle field name is (p31_email_list_assignments).
The working shuttle LOV Definition code is:
Select last_name || ', ' || first_name || ' -- ' || email_address, prim_key
From mail_recipient
order by 1;
The working shuttle Source code is:
declare
mail_list apex_application_global.vc_arr2;
i number := 1;
begin
for r in (Select mr.last_name || ', ' || mr.first_name || ' -- ' || mr.email_address, mr.prim_key
From mail_recipient mr left join
mail_recipient_list mrl
On mr.prim_key = mrl.recipient_fkey
Where mrl.list = :P31_EMAIL_LIST)
loop
mail_list(i) := r.prim_key;
i := i + 1;
end loop;
return APEX_UTIL.TABLE_TO_STRING(mail_list, ':');
end;
The working After Submit page process code is:
Begin
Merge Into MAIL_RECIPIENT_LIST mrl
Using (
Select
shuttle.column_value shuttle_cv
, db.recipient_fkey db_rfk
From
table(string_to_coll(:P31_email_list_assignments)) shuttle
left outer join mail_recipient_list db
on shuttle.column_value = db.recipient_fkey
and db.list = :P31_email_list) t
On (mrl.recipient_fkey = t.db_rfk
And mrl.list = :p31_email_list
)
When Matched
Then
Update
Set
mrl.merge_check = mrl.merge_check
-- Delete
-- Where
-- t.shuttle_cv is null
When Not Matched
Then
Insert
(recipient_fkey, list)
Values
(t.shuttle_cv, :P31_email_list);
/* The commented-out delete clause of the Merge statement never worked with this shuttle.
The following delete statement will every time this page process is called
*/
Delete from MAIL_RECIPIENT_LIST
Where instr(':' || :P31_email_list_assignments || ':',':' || recipient_fkey || ':') = 0
And list = :P31_email_list;
end;
I hope someone finds this useful.