Hi ,
i have database 11g , and i have user X and want to drop this user just once database startup .
so i used this trigger :
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CREATE OR REPLACE TRIGGER SYS.TW_drop_user
AFTER STARTUP ON DATABASE

DECLARE
created_date_schema DATE;
total_days NUMBER;
schema_name VARCHAR2 (100);
open_count number;

BEGIN
SELECT TO_DATE (created, 'dd/mm/rrrr')
INTO created_date_schema
FROM v$database;

SELECT owner
INTO schema_name
FROM dba_tables
WHERE table_name = 'RT_LICENSE' AND ROWNUM <= 1;

SELECT TRUNC (SYSDATE) - TO_DATE (created_date_schema, 'dd/mm/rrrr')
DAYS
INTO total_days
FROM DUAL;


IF total_days > 14
THEN

EXECUTE IMMEDIATE ('alter USER "' || schema_name || '" account lock ');

FOR session IN (SELECT sid, serial#
FROM v$session
WHERE username = schema_name)
LOOP
EXECUTE IMMEDIATE 'alter system disconnect session ''' || session.sid || ',' || session.serial# || ''' immediate';
END LOOP;

LOOP
SELECT COUNT(*)
INTO open_count
FROM v$session WHERE username = schema_name;
EXIT WHEN open_count = 0;
dbms_lock.sleep(0.5);
END LOOP;

EXECUTE IMMEDIATE ('DROP USER "' || schema_name || '" CASCADE ');
END IF;
EXCEPTION
WHEN OTHERS
THEN
NULL;
END;

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but nothing happen , i login to sqlplus and connect to this user and still not dropped , shutdown and start database , login with sys i even change trigger to be after log AFTER LOGON.. user not dropped !!
but if i'm running this script alone without trigger , its working fine .
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any help please , thanks in Advance.

select to_date ( created, 'dd/mm/rrrr' )
into created_date_schema
from v$database

exception
  when others then
    null;