手动修改某表的记录，弹出以下错误：
然后尝试用PL/SQL语句修改记录，十多分钟过去了，一直显示正在执行；
结论：死锁了！！
查看被锁对象：
SELECT l.session_id sid,
s.serial#,
l.locked_mode 锁模式,
l.oracle_username 登录用户,
l.os_user_name 登录机器用户名,
s.machine 机器名,
s.terminal 终端用户名,
o.object_name 被锁对象名,
s.logon_time 登录数据库时间
FROM v$locked_object l, all_objects o, v$session s
WHERE l.object_id = o.object_id
AND l.session_id = s.sid
ORDER BY sid, s.serial#;
<??http://www.2cto.com/kf/ware/vc/" target="_blank" class="keylink">vc3Ryb25nPgo8c3Ryb25nPsmxtfS4w8v4ttTP86O6PC9zdHJvbmc+CsSjsOWjumFsdGVyIHN5c3RlbSBraWxsIHNlc3Npb24g"sid,serial#' immediate; 实例：alter system kill session '7,223' immediate;