Using client identifier to populate a column

Earlier I wrote about missing dbms_session.get_client_identifier. Here is a compound trigger example using session client identifier to populate a column in a table.

drop table t;

create table t(n number, client_id varchar2(30) not null);

create or replace trigger t_iuc for insert or update on t 
  compound trigger
  cli varchar2(30);
 before statement is
  begin
   cli := SYS_CONTEXT('userenv', 'CLIENT_IDENTIFIER');
  end before statement;
 before each row is
  begin
   :new.client_id := cli;
  end before each row;
end;
/

exec dbms_session.set_identifier('rafu')

insert into t(n) select level from dual connect by level < 4;

select * from t;

1 rafu
2 rafu
3 rafu