oracle的全局临时表

基于会话的全局临时表(on commit preserve rows)
基于事务的全局临时表(on commit delete rows)

set autotrace off;

(1)建立表
//建立临时会话表
create global temporary table tmp_session1 on commit preserve rows as select * from dba_objects where 1=0;

select a.name,b.value from v$statname a join v$mystat b on a.statistic#=b.statistic# where a.name='redo size';

NAME                                      VALUE
---------------------------------------------------------------- ----------
redo size                                 100496

//建立事务临时表
create global temporary table tmp_trans1 on commit delete rows as select * from dba_objects where 1=0;

select a.name,b.value from v$statname a join v$mystat b on a.statistic#=b.statistic# where a.name='redo size';

NAME                                      VALUE
---------------------------------------------------------------- ----------
redo size                                  21912

(2)插入数据
//向临时会话表插入数据
insert into tmp_session1 select * from dba_objects;

select a.name,b.value from v$statname a join v$mystat b on a.statistic#=b.statistic# where a.name='redo size';

NAME                                      VALUE
---------------------------------------------------------------- ----------
redo size                                 512820

//向临时事务表插入数据
insert into tmp_trans1 select * from dba_objects;

select a.name,b.value from v$statname a join v$mystat b on a.statistic#=b.statistic# where a.name='redo size';

NAME                                      VALUE
---------------------------------------------------------------- ----------
redo size                                 434236


测试：
//在事务上
select count(*) from tmp_trans;

  COUNT(*)
----------
     72539

commit;

select count(*) from  tmp_trans;

  COUNT(*)
----------
     0

//在会话上
select count(*) from tmp_session1;

  COUNT(*)
----------
     72537
commit;

select count(*) from tmp_session1;

  COUNT(*)
----------
     72537
sql guoyf/guoyf
Connected.

Session altered.

LISN@orcl>select count(*) from tmp_session1;
select count(*) from tmp_session1;

  COUNT(*)
----------
       0

基于会话的临时表:

全局临时表特征：
(1)基于会话的全局临时表特征：基于会话的全局临时表则是session连接退出后，临时记录自动删除，无需手动去操做，针对不一样session访问全局临时表，看到的结果是不一样。
(2)基于事务的全局临时表在commit或者session连接退出后，临时表记录自动删除。