ORA-01940

SQL> drop user a cascade;  drop user a cascade  *  ERROR 位于第 1 行:  ORA-01940: 无法删除当前已连接的用户

解决方法:

SQL> select username,sid,serial# from v$session;  USERNAME                              SID    SERIAL#  ------------------------------ ---------- ----------                                          1          1                                          2          1                                          3          1                                          4          1                                          5          1                                          6          1                                          7          1  SYS                                     8          3  A                                       9          4  已选择9行。  SQL> alter system kill session'9,4';  系统已更改。  SQL> drop user a cascade;//删除用户以及用户表空间下所有对象  用户已丢弃。