select saddr,sid,serial#,paddr,username,status from v$session where username is not null;
alter system kill session‘195,169‘;
drop user emis cascade;
sqlplus/nolog
conn / as sysdba;
startup(shutdown immediate)
(启动侦听)lsnrctl start/stop
原文：http://www.cnblogs.com/mingjing/p/4477747.html