事务_事务隔离级别演示1和事务_事务隔离级别演示2

​ 1.read uncommitted：读未提交

演示：

​ 　　set global transaction isolation level read uncommitted；
​　　 start transaction;
​ - - 转账操作
​ 　　update account set balance = balance - 500 where id = 1;
​ 　　update account set balance = balance +500 where id = 2;

 

 

 

在开一个窗口

 

 

read committed：读已提交（Oracle)

 set global transaction isolation level read committed；

start transaction;

 转账操作
​update account set balance = balance - 500 where id = 1;

update account set balance = balance +500 where id = 2;

 

 

 

 

 

 在开一个窗口

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

事务_事务隔离级别演示2

set global transaction isolation level repeatable read;

start transaction;

 转账操作
​update account set balance = balance - 500 where id = 1;

update account set balance = balance +500 where id = 2;

 

 

在开启一个窗口

 

 

 

 

 

 

 

 

 serializable锁

set global transaction isolation level serializable;

start transaction;

 转账操作
​update account set balance = balance - 500 where id = 1;

update account set balance = balance +500 where id = 2;

 

 

 

 

 

在开一窗口