使用oracle序列+oracle定时任务获取每月从1开始的流水码

--创建序列

--入库
create sequence rk_seq;
--出库
create sequence ck_seq;
--移库
create sequence yk_seq;

--创建存储过程

create or replace procedure reset_seq(rk_seq_name in varchar2,
ck_seq_name in varchar2,
yk_seq_name in varchar2) is
l_val number;
begin
--rk
execute immediate 'select ' || rk_seq_name || '.nextval from dual'
INTO l_val;

execute immediate 'alter sequence ' || rk_seq_name || ' increment by -' ||
l_val || ' minvalue 0';

execute immediate 'select ' || rk_seq_name || '.nextval from dual'
INTO l_val;

execute immediate 'alter sequence ' || rk_seq_name ||
' increment by 1 minvalue 0';
--ck
execute immediate 'select ' || ck_seq_name || '.nextval from dual'
INTO l_val;

execute immediate 'alter sequence ' || ck_seq_name || ' increment by -' ||
l_val || ' minvalue 0';

execute immediate 'select ' || ck_seq_name || '.nextval from dual'
INTO l_val;

execute immediate 'alter sequence ' || ck_seq_name ||
' increment by 1 minvalue 0';

--yk
execute immediate 'select ' || yk_seq_name || '.nextval from dual'
INTO l_val;

execute immediate 'alter sequence ' || yk_seq_name || ' increment by -' ||
l_val || ' minvalue 0';

execute immediate 'select ' || yk_seq_name || '.nextval from dual'
INTO l_val;

execute immediate 'alter sequence ' || yk_seq_name ||
' increment by 1 minvalue 0';
end;

--创建定时任务

declare
job number;
begin
dbms_job.submit(job,
' begin reset_seq(''rk_seq'', ''ck_seq'', ''yk_seq'');end;',
sysdate,
'TRUNC(LAST_DAY(SYSDATE))+1+1/24');
end;

背景：数据WCS_TASK(WCS_任务)表中有一个WCS_ID(任务编码)的字段，任务编号规则：1位任务类型+4位年月+五位流水码 ，如12103000001  (TYPE--任务类型: 1--入库，2--出库，3--移库）

要求：新增WCS_TASK数据时，WCS_ID字段程序中自动生成，而且每个月的流水码要从1开始

难点：在于并发情况下生成流水码不能重复，并且每月重置

解决办法：利用数据库的序列来获取流水码，然后创建数据库定时任务，每个月1号重置序列

用法：数据库创建好序列和定时任务，直接在程序中查询相应序列即可获取不重复的流水码，序列的重置工作由定时任务自动执行