oracle drop user

SQL> drop user test cascade;
drop user test cascade
*
ERROR at line 1:
ORA-01940: cannot drop a user that is currently connected


SQL> select username,sid,serial# from v$session;

USERNAME                   SID     SERIAL#
------------------------------ ---------- ----------
SYSMAN                     118       43411
test                       122     483
test                       123     391
SYS                        125     626
DBSNMP                     129      48
SYSMAN                     130     247
DBSNMP                     136     113
SYSMAN                     138      15
SYSMAN                     141       3
                               143       50435
                               152       3


USERNAME                   SID     SERIAL#
------------------------------ ---------- ----------
                       153       3
SYSMAN                 158      15
                       160       1
                       161       1
                       162       1
                       163       1
                       164       1
                       165       1
                       166       1
                       167       1
                       168       1

USERNAME                   SID     SERIAL#
------------------------------ ---------- ----------
                       169       1
                       170       1

SQL>alter system kill session '122,483';

SQL> drop user test cascade;

 (**)如果在drop 后还提示ORA-01940:无法删除当前已链接的用户，说明还有连接的session，可以通过查看session的状态来确定该session是否被kill 了，用如下语句查看： ------------------------------------- select saddr,sid,serial#,paddr,username,status from v$session where username is not null 结果如下(以我的库为例)： saddr                     sid          serial#            paddr              username              status -------------------------------------------------------------------------------------------------------- 564A1E28              513           22974            569638F4       NETBNEW             ACTIVE564A30DC              514          18183             569688CC        NETBNEW           INACTIVE564A5644             516           21573            56963340       NETBNEW            INACTIVE564B6ED0              531         9                   56962D8C        NETBNEW            INACTIVE564B8184              532          4562                56A1075C        WUZHQ                KILLED   status 为要删除用户的session状态，如果还为inactive，说明没有被kill掉，如果状态为killed，说明已kill。 由此可见，WUZHQ这个用户的session已经被杀死。此时可以安全删除用户。
User dropped.