1、插入

insert into dept values(50, 'soft', 'Guangzhou');

insert into dept(deptno, dname) values(60, 'software test');

insert into dept select * from dept where deptno = 20;

2、删除

delete from dept where deptno = 20;

delete from dept;

3、修改

update dept set dname = dname || ' ^.^' where deptno = 20;

4、事务

每个修改语句完成后都可以回滚或提交，即rollback、commit；

eg:

insert into dept values(50, 'soft', 'Guangzhou');

rollback;

这样就回滚了，等于上面的没有插入；如果commit就提交了，此后如果再rollback也无力回天了。

下面这样也是无法回滚的：

insert into dept values(50, 'soft', 'Guangzhou');

create table temp as select * from dept;

rollback;

再次查询，发现无法回滚；同样增删改后面运行grant/create语句也是无法回滚的；