Question

We have an application that creates a table with a randomly generated name. I would like to create a trigger on this table.Since I do not know the name of the tabe I would like to get it from the all_table view. How can I go about achieveing something like this?

    create or replace trigger t1      
after insert or update on (select table_name from all_tables where owner = 'CustomAPP' and table_name like 'STAGE_%')  
     -- for each row
    declare
      -- local variables here
    begin

    end t1;

The SQL above obviously gives an error because of the select clause after the create trigger instead of a table name. Please advise

Answer 1

You would need to make the entire CREATE TRIGGER dynamic in order to do this. Something like this should work. You probably want to make the trigger name depend on the name of the table assuming there could be multiple tables that your query against ALL_TABLES might return multiple rows. And you certainly want the trigger to do something rather than having an empty body.

SQL> create table stg_12345( col1 number );

Table created.

SQL> begin
  2    for x in (select *
  3                from user_tables
  4               where table_name like 'STG%')
  5    loop
  6      execute immediate
  7        'create or replace trigger trg_foo ' ||
  8        ' before insert on ' || x.table_name ||
  9        ' for each row ' ||
 10        'begin ' ||
 11        '  null; ' ||
 12        'end;';
 13    end loop;
 14  end;
 15  /

PL/SQL procedure successfully completed.

SQL> select count(*) from user_triggers where trigger_name = 'TRG_FOO';

  COUNT(*)
----------
         1

Of course, the idea of an application that creates tables on the fly is one that frightens me to the core. If you have any control over that, I would strongly suggest reconsidering the architecture.