Oracle中一般将自增sequence重置为初始1时,都是删除再重建,这种方式有很多弊端,依赖它的函数和存储过程将失效,需要重新编译。不过还有种巧妙的方式,不用删除,利用步长参数,先查出sequence的nextval,记住,把递增改为负的这个值(反过来走),然后再改回来。

假设需要修改的序列名:seq_name

1、select seq_name.nextval from dual;  //假设得到结果5656

2、alter sequence seq_name increment by -5655  //注意是-(n-1)

3、select seq_name.nextval from dual;  //再查一遍,走一下,重置为1了

4、alter sequence seq_name increment by 1;  //还原

可以写个存储过程,以下是完整的存储过程,然后调用传参即可:

 create or replace procedure seq_reset(v_seqname varchar2)
as cur_seq number(28);
tsql varchar2(200);
begin
execute immediate 'select ' || v_seqname || '.nextval from dual' into cur_seq;
cur_seq:=-(cur_seq-1);
tsql:='alter sequence ' || v_seqname || ' increment by ' || cur_seq;
execute immediate tsql;
execute immediate 'select ' || v_seqname || '.nextval from dual' into cur_seq;
tsql:='alter sequence ' || v_seqname || ' increment by 1';
execute immediate tsql;
end seq_reset;
/

需要调用时,执行(如sequence名称为SEQ_QT_PRCS_ID):

 BEGIN
seq_reset('SEQ_QT_PRCS_ID');
END;
/

转载自《Oracle重置序列(不删除重建方式)》

05-02 10:00