--构建测试用表空间
SQL> create tablespace tbs_one datafile 'c:\tbs_one_1' size 20m;
 
Tablespace created
 
 --构建测试用户1，所属表空间为tbs_one
SQL> create user user_1 identified by system default tablespace tbs_one account unlock;
 
User created
 
SQL> grant resource,connect to user_1;
 
Grant succeeded
 
 
 --构建测试用户2，所属表空间为tbs_one
SQL> create user user_2 identified by system default tablespace tbs_one account unlock;
 
User created
 
SQL> grant resource,connect to user_2;
 
Grant succeeded
 
 --连接到测试用户1,并构建测试表
SQL> conn user_1/system@orcl
Connected to Oracle Database 11g Enterprise Edition Release 11.2.0.1.0
Connected as user_1
 
SQL> create table user_1_table(a int);
 
Table created
 
SQL> insert into user_1_table values(1);
 
1 row inserted
 
SQL> commit;
 
Commit complete
 
 --以sysdba登陆，并删除测试用户2
SQL> conn sys/system@orcl as sysdba
Connected to Oracle Database 11g Enterprise Edition Release 11.2.0.1.0
Connected as SYS
 
SQL> drop user user_2 cascade;--注：加cascade选项
 
User dropped
 
SQL>  conn user_1/system@orcl
Connected to Oracle Database 11g Enterprise Edition Release 11.2.0.1.0
Connected as user_1
 
SQL> select * from user_1_table;
 
                                      A
---------------------------------------
                                      1
                                     
小结：在多个用户使用同一个表空间的情况下
      1,2个oracle用户可以共同拥有一个表空间                                    
      2,删除一个oracle用户，不会影响另一个用户的数据