======================================================会话1============================================
在第一个会话创建临时表，插入数据
SQL> create global temporary table tmp_emps on commit preserve rows as
2 select * from employees where 1=2;
Table created.
SQL> select * from tmp_emps;
no rows selected
SQL> insert into tmp_emps select * from employees where department_id=30;
6 rows created.
SQL> commit;
====================================================会话2============================================
在第二个会话中查不到会话1中插入的数据，在会话2中临时表插入数据
SQL> select count(*) from tmp_emps;
COUNT(*)
----------
0
SQL> insert into tmp_emps select * from employees where department_id=50;
45 rows created.
SQL> commit;
Commit complete.
====================================================会话1=========================================
会话1中将表截断
SQL> truncate table tmp_emps;
Table truncated.
SQL> select * from tmp_emps;
no rows selected
====================================================会话2========================================
如果会话2不断开，则不影响会话2中temp表中的数据
SQL> select count(*) from tmp_emps;
COUNT(*)
----------
45
断开重连之后，会话2中临时表的数据将丢失
SQL> disconnect;
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL> conn hr/oracle
Connected.
SQL> select count(*) from tmp_emps;
COUNT(*)
----------
0
在会话2中删除表
SQL> drop table tmp_emps;
Table dropped.
SQL> select count(*) from tmp_emps;
select count(*) from tmp_emps
*
ERROR at line 1:
ORA-00942: table or view does not exist
====================================================会话2========================================
会话1即使不断开重连，也无法找到表
SQL> select * from tmp_emps;
select * from tmp_emps
*
ERROR at line 1:
ORA-00942: table or view does not exist
