提取Oracle当前用户名，机器名，IP的方法
select sysdate 当前时间,
sys.login_user 数据库用户,
machine 登录机器名,
SYS_CONTEXT('USERENV', 'IP_ADDRESS') 登录IP,
program 应用程序
from v$session
where AUDSID = USERENV('SESSIONID');
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