1. 什么是序列
![](https://images2015.cnblogs.com/blog/326197/201704/326197-20170422165745196-694013350.png)
2. 创建序列
![](https://images2015.cnblogs.com/blog/326197/201704/326197-20170422165905165-219876686.png)
3. 查询序列
![](https://images2015.cnblogs.com/blog/326197/201704/326197-20170422165939196-1705224716.png)
4. nextval和currval序列
![](https://images2015.cnblogs.com/blog/326197/201704/326197-20170422170001102-1526446243.png)
查看nextval或者是currval的值:
select sequence.nextval from dual;
select sequence.currval from dual;
5. 使用序列注意事项
![](https://images2015.cnblogs.com/blog/326197/201704/326197-20170422170040821-813593145.png)
6. 修改序列
![](https://images2015.cnblogs.com/blog/326197/201704/326197-20170422170102087-1359509846.png)
7. 删除序列
![](https://images2015.cnblogs.com/blog/326197/201704/326197-20170422170153040-1852166718.png)
8. 什么是索引
![](https://images2015.cnblogs.com/blog/326197/201704/326197-20170422170320181-1200014502.png)
9. 创建索引
![](https://images2015.cnblogs.com/blog/326197/201704/326197-20170422170355102-916002902.png)
10. 什么时候创建索引
![](https://images2015.cnblogs.com/blog/326197/201704/326197-20170422170453274-897690684.png)
11. 什么时候不创建索引
![](https://images2015.cnblogs.com/blog/326197/201704/326197-20170422170601618-1823325597.png)
12. 查询索引
![](https://images2015.cnblogs.com/blog/326197/201704/326197-20170422170735837-544940666.png)
13. 删除索引
![](https://images2015.cnblogs.com/blog/326197/201704/326197-20170422170812431-1048894770.png)
14. 同义词synonym
![](https://images2015.cnblogs.com/blog/326197/201704/326197-20170422170935384-4145404.png)