MySQL第十三次作业-事务管理

1、创建一个名为chapter06的数据库

2、使用chapter06数据库

3、创建一个名为account的表

create table account(
-> id int primary key auto_increment,
-> name varchar(40),
-> money float
-> );

4、往表中插入数据
insert into account(name,money) values
-> (‘a’,1000),
-> (‘b’,1000);

5、查询表中数据

6、开启一个事务然后通过update语句将a账户的100元钱转给b用户，最后提交事务。

start transaction;
update account set money=money-100 where name = ‘a’;
update account set money=money+100 where name = ‘b’;
commit;

7、查询表中余额
select * from account;

8、开启一个事务然后通过update语句将b账户的100元钱转给a用户

start transaction;
update account set money=money+100 where name = ‘a’;
update account set money=money-100 where name = ‘b’;

9、再查询表中余额
select * from account;

10、先退出MySQL数据库，再登录MySQL数据库，然后再使用chapter06数据库，在查询余额

11、开启一个事务然后通过update语句将b账户的100元钱转给a用户，然后使用commit语句来提交事务。

start transaction;
update account set money = money +100 where name =‘a’;
update account set money = money -100 where name =‘b’;
commit;

12、重新登录数据库然后再查询余额

13、开启一个事务，通过update语句将a账户的100元钱转给b账户。
start transaction;
update account set money = money -100 where name =‘a’;
update account set money = money +100 where name =‘b’;

14、然后查询A、B账户的金额；
select * from account;

15、从查询结果可以看出，a账户的100元钱转给b账户了，但是事务还没有提交，我们还可以执行事务回滚，操作如下：

rollback;

16、查询A、B账户的余额

select * from account;

17、将b账户的隔离级别改为read uncommitted；

set session transaction isolation level read uncommitted;

18、设置b账户事务隔离级别：

select @@transaction_isolation;

19、演示脏读：

start transaction;
select * from account;

20、在a账户中开启一个事务，并在当前窗口中执行转账功能，但不提交事务。

start transaction;
update account set money = money - 100 where name =‘a’;
update account set money = money + 100 where name =‘b’;

21、然后再查询余额信息
select * from account;

22、将上一步开启的事务进行回滚

rollback;
select * from account;

23、设置b账户中事务的隔离级别

set session transaction isolation level read committed;

24、验证是否出现脏读：

start transaction;
select * from account;

25、在a账户中开启一个事务，并在该事务中实现转账功能

start transaction;
update account set money = money -100 where name = ‘a’;
update account set money = money +100 where name = ‘b’;

26、再次查询各账户的余额信息。

select * from account;

27、演示不可重复读

start transaction;
select * from account;

28、在a账户中不用开启事务，直接使用update语句执行更新操作即可

update account set money = money -100 where name = ‘a’;

29、查询a账户的余额

select * from account;

30、当a账户的更新语句完成后，查询b账户的余额

select * from account;

31、设置b账户中事务的隔离级别

set session transaction isolation level repeatable read;

32、验证是否出现不可重复读

start transaction;
select * from account;

33、幻读

set session transaction isolation level read committed;

34、演示幻读

start transaction;
select * from account;




insert into account(name,money) values(‘c’,1000);

select * from account;

set session transaction isolation level repeatable read;

35、验证是否出现幻读

start transaction;
select * from account;


select * from account;

select * from account;

36、可串行化


start transaction;
select * from account;

37、演示可串行化

start transaction;
select * from account;

start transaction;