oracle - SERVEROUTPUT shows results one after another execution -

when execute following trigger code compiled. after inserting data, serveroutput says '1 row inserted' trigger result ('user example has insrted data') didn't displayed.

then after execution of pl/sql previous trigger result appears on display. should solve issue?

here trigger , insertion command , results,

/ set serveroutput on;  create or replace trigger btr_superheros before insert on superheros each row enable  declare     v_user varchar2(30); begin     select user v_user dual;     dbms_output.enable();     dbms_output.put_line('user:' ||v_user||' has inserted data'); end; / 

result - trigger btr_superheros compiled

insert superheros values('superman');

result - 1 row inserted. (didn't shows dbms_output)

you need set serveroutput on in client application (sql*plus, sql developer etc) in session run statement, otherwise won't know want fetch , display output buffer when statement completes. set server output on prior creating trigger client setting , doesn't set permanently trigger.

please confirm whether test case run single session, this:

sql*plus: release 12.1.0.1.0 production on tue aug 15 08:17:48 2017  copyright (c) 1982, 2013, oracle.  rights reserved.  last successful login time: tue aug 15 2017 08:14:08 +01:00  connected to: oracle database 12c enterprise edition release 12.1.0.1.0 - 64bit production partitioning, olap, advanced analytics , real application testing options  sql> set serveroutput on; sql> sql> create or replace trigger btr_superheros   2  before insert on superheros   3  each row   4  enable   5   6  declare   7      v_user varchar2(30);   8  begin   9      select user v_user dual;  10      dbms_output.enable();  11      dbms_output.put_line('user:' ||v_user||' has inserted data');  12  end;  13  /  trigger created.  sql> insert superheros values('superman'); user:william has inserted data  1 row created. 

note not recommended call dbms_output.enable. the documentation:

you should avoid having application code invoke either disable procedure or enable procedure because subvert attempt of external tool sql*plus control whether or not display output.

you can assign values using assignment := operator instead of select into statement. trigger therefore written as:

create or replace trigger btr_superheros before insert on superheros each row enable declare     v_user user_users.username%type := sys_context('userenv', 'current_schema'); begin     dbms_output.put_line('user: ' ||v_user||' inserted value '''||:new.name||''''); end; /