System Tables Views Oracle PLSQL

SQL>
SQL> create table EMP (
  2        course_id   number not null,
  3        course_name varchar2(60) not null,
  4        subject_id  number not null,
  5        duration    number(2),
  6        skill_lvl   varchar2(12) not null
  7  );
Table created.
SQL>
SQL> select tablespace_name, table_name
  2  from user_tables
  3  where table_name in ('EMP', 'DEPT')
  4  order by 1, 2;
TABLESPACE_NAME                TABLE_NAME
------------------------------ ------------------------------
SYSTEM                         EMP
SQL>
SQL>
SQL> select segment_name, tablespace_name
  2  from user_segments
  3  where segment_name = 'EMP';
SEGMENT_NAME                                                                      TABLESPACE_NAME
--------------------------------------------------------------------------------- ------------------------------
EMP                                                                               SYSTEM
SQL>
SQL> alter table emp move
  2  tablespace users;
Table altered.
SQL>
SQL>
SQL> select segment_name, tablespace_name
  2  from user_segments
  3  where segment_name = 'EMP';
SEGMENT_NAME                                                                      TABLESPACE_NAME
--------------------------------------------------------------------------------- ------------------------------
EMP                                                                               USERS
SQL>
SQL> drop table emp;
Table dropped.
SQL>
SQL>
SQL>
select default_tablespace, temporary_tablespace from dba_users by username
select username, default_tablespace, temporary_tablespace
from dba_users
where default_tablespace = 'SYSTEM' or temporary_tablespace = 'SYSTEM';
alter user scott
default tablespace users;
select default_tablespace, temporary_tablespace
from dba_users
where username = 'SCOTT';