事物默认自动提交AUTOCOMMIT

修改为非自动提交的方式有两种：
1、# \set AUTOCOMMIT off    --注意此处的AUTOCOMMIT要大写，小写无效
highgo=# \echo :autocommit
:autocommit
highgo=# \echo :AUTOCOMMIT
on
highgo=# \set autocommit off
highgo=# \echo :AUTOCOMMIT
on
highgo=# \set AUTOCOMMIT off
highgo=# \echo :AUTOCOMMIT
off
highgo=# select * from test;
 id | name 
----+------
(0 rows)


highgo=# insert into test values (1);
INSERT 0 1
highgo=# insert into test values (2);
INSERT 0 1
highgo=# select * from test;
 id | name 
----+------
  1 | 
  2 | 
(2 rows)


highgo=# rollback;
ROLLBACK
highgo=# select * from test;
 id | name 
----+------
(0 rows)




2、显示使用BEGIN
highgo=# \echo :AUTOCOMMIT
on
highgo=# begin;                ---此处begin大小写都生效
BEGIN
highgo=# 
highgo=# select * from test;
 id | name 
----+------
(0 rows)


highgo=# insert into test values (1);
INSERT 0 1
highgo=# select * from test;
 id | name 
----+------
  1 | 
(1 row)


highgo=# rollback;
ROLLBACK
highgo=# select * from test;
 id | name 
----+------
(0 rows)




++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
highgo=# show autocommit;
 autocommit 
------------
 on
(1 row)


highgo=# \set AUTOCOMMIT off
highgo=# show autocommit;
 autocommit 
------------
 on
(1 row)


highgo=# \echo :AUTOCOMMIT
off
highgo=# \echo :autocommit
:autocommit


++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
show autocommit;和\echo :autocommit的区别
highgo=# \set autocommit on
highgo=# show autocommit;
 autocommit 
------------
 on
(1 row)


highgo=# \set AUTOCOMMIT OFF
highgo=# show autocommit;   
 autocommit 
------------
 on
(1 row)


highgo=# \SET AUTOCOMMIT off
Invalid command \SET. Try \? for help.
highgo=# show autocommit;
 autocommit 
------------
 on
(1 row)


highgo=# \SET autocommit off
Invalid command \SET. Try \? for help.
highgo=# \set AUTOCOMMIT off
highgo=# show autocommit;
 autocommit 
------------
 on
(1 row)


highgo=# \set autocommit off
highgo=# show autocommit;
 autocommit 
------------
 on
(1 row)


highgo=# \set autocommit  off
highgo=# show autocommit;
 autocommit 
------------
 on
(1 row)


highgo=# \echo :AUTOCOMMIT
off
highgo=# show autocommit;
 autocommit 
------------
 on
(1 row)
highgo=# \set autocommit on
highgo=# \echo :autocommit
on
highgo=# show autocommit;
 autocommit 
------------
 on
(1 row)


++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++