oracle 更改序列的初始值____oracle

 declare v_in varchar2(1024); v_start int;v_end int ; v_table varchar2(200);v_seq varchar2(200);v_table_seq varchar2(100);    begin      v_table:='jx_khfa';--表名      v_seq:='seq_jx_khfa';--序列名      v_table_seq:='id';--表欄位對應序列     v_in:= 'select max('||v_table_seq||') from '||v_table;--查詢表中最大值    execute immediate v_in into v_start;     v_in:= 'select '||v_seq||'.nextval from dual ';--查詢下一個序列值    execute immediate v_in into v_end;      v_in:= 'ALTER SEQUENCE '||v_seq||' INCREMENT BY '||to_char(v_start-v_end+1);--更改步長     execute immediate v_in;    execute immediate 'select '||v_seq||'.nextval from dual ' into v_end;--執行一次序列    execute immediate 'ALTER SEQUENCE '||v_seq||' INCREMENT BY 1';--改回步長      end;