oracle增加sequence

（1）删除序列;  （2）重新创建； 这个方法比较简单粗暴。

drop sequence  sequence_name;

create sequence   sequence_name

minvalue 1                                                             //最小值

maxvalue 999999999999999999999999999  //最大值

start with  10                                                         //初始值

increment by 1                                                     //步长

cache 20                                                               //序列号缓存

order;                                                                    //按顺序产生序列值