mysql事务

事务：https://blog.youkuaiyun.com/w_linux/article/details/79666086
事务四个特性：https://blog.youkuaiyun.com/longxingzhiwen/article/details/53912475
https://blog.youkuaiyun.com/qq_39521554/article/details/80240841

关于脏读，不可重复读，幻象读的理解https://www.cnblogs.com/qkhh/p/4736594.html