需求：默认无法直接删除Oracle的users表空间，直接尝试删除会有报错如下：
SQL> drop tablespace users including contents and datafiles;
drop tablespace users including contents and datafiles
*
ERROR at line 1:
ORA-12919: Can not drop the default permanent tablespace
报错很明确，USERS目前作为数据库目前默认的永久表空间，暂不支持直接删除。
进一步查询，看到有很多用户的确是默认用到了USERS表空间：
SQL>
USERNAME DEFAULT_TABLESPACE CREATED
------------------------------ ------------------------------ ---------
SYSRAC USERS 04-JAN-23
SYSTEM SYSTEM 04-JAN-23
SYSBACKUP USERS 04-JAN-23
AUDSYS USERS 04-JAN-23
SYSKM USERS 04-JAN-23
SYS SYSTEM 04-JAN-23
SYSDG USERS 04-JAN-23
OUTLN SYSTEM 04-JAN-23
GSMADMIN_INTERNAL SYSAUX 04-JAN-23
GSMUSER USERS 04-JAN-23
DIP USERS 04-JAN-23
USERNAME DEFAULT_TABLESPACE CREATED
------------------------------ ------------------------------ ---------
XS$NULL SYSTEM 04-JAN-23
REMOTE_SCHEDULER_AGENT USERS 04-JAN-23
DBSFWUSER SYSAUX 04-JAN-23
ORACLE_OCM USERS 04-JAN-23
SYS$UMF USERS 04-JAN-23
DBSNMP SYSAUX 04-JAN-23
APPQOSSYS SYSAUX 04-JAN-23
GSMCATUSER USERS 04-JAN-23
GGSYS SYSAUX 04-JAN-23
XDB SYSAUX 04-JAN-23
ANONYMOUS SYSAUX 04-JAN-23
USERNAME DEFAULT_TABLESPACE CREATED
------------------------------ ------------------------------ ---------
WMSYS SYSAUX 04-JAN-23
OJVMSYS USERS 04-JAN-23
CTXSYS SYSAUX 04-JAN-23
MDSYS SYSAUX 04-JAN-23
ORDSYS USERS 04-JAN-23
ORDDATA USERS 04-JAN-23
ORDPLUGINS USERS 04-JAN-23
SI_INFORMTN_SCHEMA USERS 04-JAN-23
OLAPSYS SYSAUX 04-JAN-23
MDDATA USERS 04-JAN-23
APEX_180200 SYSAUX 04-JAN-23
USERNAME DEFAULT_TABLESPACE CREATED
------------------------------ ------------------------------ ---------
FLOWS_FILES SYSAUX 04-JAN-23
APEX_PUBLIC_USER USERS 04-JAN-23
APEX_INSTANCE_ADMIN_USER USERS 04-JAN-23
PDBADMIN USERS 04-JAN-23
HR SYSAUX 04-JAN-23
JINGYU USERS 06-JAN-23
TEAM USERS 01-MAR-23
40 rows selected.
但现在XTTS测试，客户现有源端的users表空间也需要迁移（有用户数据，注意我们并不推荐在users存放用户数据）
如果真想删除，也是可以的，就是修改默认表空间，但还需要考虑USERS里面是否有数据要迁移，比较麻烦。
现场实施的兄弟提出能否重命名users表空间，这是个好主意，实测是OK，操作也很简单，一条语句搞定：
SQL> alter tablespace users rename to user1;
Tablespace altered.
瞬间执行完成，然后再查用户的默认表空间，也已经从users已经变成user1：
SQL> select USERNAME, DEFAULT_TABLESPACE, CREATED from dba_users order by 3;
USERNAME DEFAULT_TABLESPACE CREATED
------------------------------ ------------------------------ ---------
SYSRAC USER1 04-JAN-23
SYSTEM SYSTEM 04-JAN-23
SYSBACKUP USER1 04-JAN-23
AUDSYS USER1 04-JAN-23
SYSKM USER1 04-JAN-23
SYS SYSTEM 04-JAN-23
SYSDG USER1 04-JAN-23
OUTLN SYSTEM 04-JAN-23
GSMADMIN_INTERNAL SYSAUX 04-JAN-23
GSMUSER USER1 04-JAN-23
DIP USER1 04-JAN-23
USERNAME DEFAULT_TABLESPACE CREATED
------------------------------ ------------------------------ ---------
XS$NULL SYSTEM 04-JAN-23
REMOTE_SCHEDULER_AGENT USER1 04-JAN-23
DBSFWUSER SYSAUX 04-JAN-23
ORACLE_OCM USER1 04-JAN-23
SYS$UMF USER1 04-JAN-23
DBSNMP SYSAUX 04-JAN-23
APPQOSSYS SYSAUX 04-JAN-23
GSMCATUSER USER1 04-JAN-23
GGSYS SYSAUX 04-JAN-23
XDB SYSAUX 04-JAN-23
ANONYMOUS SYSAUX 04-JAN-23
USERNAME DEFAULT_TABLESPACE CREATED
------------------------------ ------------------------------ ---------
WMSYS SYSAUX 04-JAN-23
OJVMSYS USER1 04-JAN-23
CTXSYS SYSAUX 04-JAN-23
MDSYS SYSAUX 04-JAN-23
ORDSYS USER1 04-JAN-23
ORDDATA USER1 04-JAN-23
ORDPLUGINS USER1 04-JAN-23
SI_INFORMTN_SCHEMA USER1 04-JAN-23
OLAPSYS SYSAUX 04-JAN-23
MDDATA USER1 04-JAN-23
APEX_180200 SYSAUX 04-JAN-23
USERNAME DEFAULT_TABLESPACE CREATED
------------------------------ ------------------------------ ---------
FLOWS_FILES SYSAUX 04-JAN-23
APEX_PUBLIC_USER USER1 04-JAN-23
APEX_INSTANCE_ADMIN_USER USER1 04-JAN-23
PDBADMIN USER1 04-JAN-23
HR SYSAUX 04-JAN-23
JINGYU USER1 06-JAN-23
TEAM USER1 01-MAR-23
40 rows selected.
查询数据库默认永久表空间也都变成了USER1：
SQL> SELECT PROPERTY_VALUE
FROM DATABASE_PROPERTIES
WHERE PROPERTY_NAME = 'DEFAULT_PERMANENT_TABLESPACE'; 2 3
PROPERTY_VALUE
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
USER1