APEX Collection Loading in Pre-Rendering Process: Error: WWV_FLOW_COLLECTIONS_UK

Question

I am running a delete/creation of an APEX Collection from pre process (code below) and am running into the following error once in a blue moon.

I saw a couple posts on this error, but they seem to be related to a different issue. There were some comments about the error being caused by the user multi clicking a button that runs this process twice, but this is an on load PL/SQL process.

Has anyone been able to fix this error consistently?

ORA-00001: unique constraint (FLOWS_030000.WWV_FLOW_COLLECTIONS_UK) violated

IF APEX_COLLECTION.COLLECTION_EXISTS('DWLOAD') then

APEX_COLLECTION.DELETE_COLLECTION (
   'DWLOAD');
   
end if;

APEX_COLLECTION.CREATE_COLLECTION_FROM_QUERY_B(
    p_collection_name => 'DWLOAD',
    p_query           => 'select a.seq, 
b.PWSID,  
b.pws_pop_served_count 

from RELATED_PWS a, SYSTEM_INFO b
where a.fk_pwsid = b.pwsid and  seq=  ' ||  :P77_SEQ || '');

Execution options for the Pre Process > "Once per page visit"

Thanks,

Update::

So I was able to replicate it by rapid clicking on the link to load the page. So then the page load runs multiple times. I am looking to see if I can show processing on the href link. For button page submissions I added a DA with Show Processing Page submit which seems to block the multi click.

Answer 1

maybe use server-side condition will solve the problem.

plsql -> IF APEX_COLLECTION.COLLECTION_EXISTS('collection_name') then 
            return false; 
         ELSE 
            return true;
         END IF;