全局临时表包括：

基于会话的全局临时表(commit preserve rows)

基于事务的全局临时表(on commit delete rows)

注意：实验在两个不同的会话做

(1)创建表

//创建临时会话表
LISN@orcl>create global temporary table tmp_session1 on commit preserve rows as select * from dba_objects where 1=0;LISN@orcl>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

另一个会话

//创建事务临时表
LISN@orcl>create global temporary table tmp_trans1 on commit delete rows as select * from dba_objects where 1=0;LISN@orcl>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
LISN@orcl>insert into tmp_session1 select * from dba_objects;LISN@orcl>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

在临时事务会话

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

（3）测试

//在事务上那个会话上

LISN@orcl>select count(*) from tmp_trans;COUNT(*)
----------72539                            --注意有数据LISN@orcl>commit;
commit;                               --提交一下LISN@orcl>select count(*) from  tmp_trans; --注意提交后没数据COUNT(*)
----------0

//在会话上

LISN@orcl>select count(*) from tmp_session1;        --注意有数据
select count(*) from tmp_session1;COUNT(*)
----------72537LISN@orcl>commit;                                    --提交一下
commit;Commit complete.LISN@orcl>select count(*) from tmp_session1;        --依然有数据
select count(*) from tmp_session1;COUNT(*)
----------72537SYS@orcl>conn lisn/lisn                            --quit，重新链接
conn lisn/lisn
Connected.Session altered.LISN@orcl>select count(*) from tmp_session1;        --查询无数据
select count(*) from tmp_session1;COUNT(*)
----------

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链接退出后，临时记录自动删除，无需手动去操作，针对不同session访问全局临时表，看到的结果是不同。

(2)基于事务的全局临时表在commit或者session链接退出后，临时表记录自动删除。

1.创建表