sql索引详解，回滚操作

1.索引

【参考】https://www.cnblogs.com/sheseido/p/5825441.html
https://www.cnblogs.com/AK2012/archive/2013/01/04/2844283.html

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2.回滚

select * from t_newstype
-----------------------------------
savepoint s_1;//设置一个保存点

insert into t_newstype(typename) values ('qq');

savepoint s_2;//设置保存点2

insert into t_newstype(typename) values ('ww');

rollback to savepoint s_2;//回滚到保存点2
commit;//提交

[参考]https://blog.csdn.net/weixin_38323645/article/details/82859058
https://www.cnblogs.com/youseiraws/p/8621334.html