oracle函数sys_context

select sys_context('USERENV','terminal') 当前会话终端标识符,
        sys_context('USERENV','language') 语言,
        sys_context('USERENV','db_name') 当前的数据库实例名称,
        sys_context('USERENV','session_user') 当前会话的数据库,
        sys_context('USERENV','current_schema')  查看当前方案 from dual;