Using Oracle Advanced Queues to monitor when a database table column is updated

问题

Env: Oracle 12c

I am new to Oracle Advanced Queues (AQ) and it looks like it's supposed to be the best approach to use instead of polling.

Based on this, I want to utilise AQ to be used based on the following trigger:

CREATE OR REPLACE TRIGGER MY_TRG  
AFTER UPDATE OF STATUS ON "MY_TABLE"  
REFERENCING NEW AS NEW OLD AS OLD  
FOR EACH ROW  
declare  
   v_status    INTEGER;  
begin      
    if :OLD.status = 'ERROR' and (:NEW.status = 'OK' or :NEW.status = 'ERROR') then  
      --
      -- do some Advanced Queue processing here ?
      --   
    end if;
end;  

So instead of polling when the STATUS column is updated, is it possible to have some type of CALLBACK feature using AQs?

I basically need a means of knowing when the STATUS column is updated in order to perform some other operation when this occurs.

回答1:

FYI, I have taken the links/information provided from the comments as well as other sites to base my solution using Oracle Advanced Queues.

Another link that was provided to me for this very purpose was:

https://markhoxey.wordpress.com/2016/03/01/asynchronous-processing-using-aq-callback/

To better answer this, I used the sample code that Mark Hoxey provided within his article, specifically the PL/SQL CALLBACK routine that was invoked via my table trigger, during a STATUS update.

You can see all available code here:

https://onedrive.live.com/?id=B48A94826582EA7D%2158434&cid=B48A94826582EA7D

This is by far the best option to use when it comes to asynchronous processing instead of polling tables with scheduled jobs.

来源：https://stackoverflow.com/questions/61582908/using-oracle-advanced-queues-to-monitor-when-a-database-table-column-is-updated