oracle的全局臨時表

基於會話的全局臨時表(on commit preserve rows)
基於事務的全局臨時表(on commit delete rows)

set autotrace off;

(1)建立表
//建立臨時會話表
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

//建立事務臨時表
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)插入數據
//向臨時會話表插入數據
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

//向臨時事務表插入數據
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


測試：
//在事務上
select count(*) from tmp_trans;

  COUNT(*)
----------
     72539

commit;

select count(*) from  tmp_trans;

  COUNT(*)
----------
     0

//在會話上
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

基於會話的臨時表:

全局臨時表特徵：
(1)基於會話的全局臨時表特徵：基於會話的全局臨時表則是session連接退出後，臨時記錄自動刪除，無需手動去操做，針對不一樣session訪問全局臨時表，看到的結果是不一樣。
(2)基於事務的全局臨時表在commit或者session連接退出後，臨時表記錄自動刪除。