I need write code executable at one time defined

Question

I need write a code what a one time defined trigger a pl/sql, i know that command exist but in this moments not remember this command please help me.
Thanks

Answer 1

I am not sure if this is what you are looking for, but you can add a section at the end of a package body that will be executed one time only, when the package is first invoked within the user session. Although it must be placed at the end of the package body, it will be executed just one time before anything else in the package is executed. Here is an example:
SQL> CREATE OR REPLACE PACKAGE test_one_time_only
  2  AS
  3    PROCEDURE every_time;
  4  END test_one_time_only;
  5  /
Package created.
SQL> CREATE OR REPLACE PACKAGE BODY test_one_time_only
  2  AS
  3    -- this will execute every time:
  4    PROCEDURE every_time
  5    IS
  6    BEGIN
  7      DBMS_OUTPUT.PUT_LINE ('every time');
  8    END every_time;
  9 
10  -- this will execute one time only:
11  BEGIN
12    DBMS_OUTPUT.PUT_LINE ('one time only');
13 
14  END test_one_time_only;
15  /
Package body created.
SQL> SET SERVEROUTPUT ON
SQL> EXEC test_one_time_only.every_time
one time only
every time
PL/SQL procedure successfully completed.
SQL> EXEC test_one_time_only.every_time
every time
PL/SQL procedure successfully completed.
SQL> EXEC test_one_time_only.every_time
every time
PL/SQL procedure successfully completed.