1、创建允许登录用户表

CREATE TABLE "CHF"."LOG$LOGIN_OS"
  (
    "OS_USER" VARCHAR2(60 BYTE)
  )

2、创建触发器实现限制用户登录

create or replace
TRIGGER TR_LOGIN_RECORD_TEST
AFTER logon ON DATABASE
DECLARE
mtSession v$session%ROWTYPE;
CURSOR cSession(iiQuerySid IN NUMBER) IS
   SELECT * FROM v$session where USERNAME is not null
    and nvl(osuser,'x') <> 'SYSTEM'   and type <> 'BACKGROUND' and audsid = iiQuerySid;
  USER_NUM NUMBER(5);
  V_SQL VARCHAR2(100);
BEGIN
OPEN cSession(userenv('SESSIONID'));
  FETCH cSession INTO mtSession;
  IF cSession%FOUND THEN
  select count(*) into USER_NUM FROM CHF.LOG$LOGIN_OS WHERE OS_USER=mtSession.Osuser;
  IF USER_NUM!=0 THEN
  V_SQL:=' alter system kill session '||''''||mtSession.Sid||','||mtSession.Serial#||'''';
  EXECUTE IMMEDIATE V_SQL;
  END IF;
  END IF;
  CLOSE cSession;
EXCEPTION
  WHEN OTHERS THEN
   -- dbms_output.put_line('登记登录信息错误：'||SQLERRM);
    RAISE;
END;

注：使用sysdba帐号创建触发器，因为在oracle中user不能kill掉自己的session，如果是用sysdba那么就可以kill掉其他的任何非自身的session