背景
公司存证产品升级，随着数据量的增加，存证产品线按业务分表，导致以往的存证关联数据需要做数据同步更新。版本发布前，通过当前存储过程解决数据升级问题，当前存储过程主要通过查询osv_service_evidence表中的存证记录总数，通过对数据做分页查询，更新evi_doc_refs表中的docEid 即osv_service_evidence表的eid。
名词解释
存储过程（Stored Procedure）是在大型数据库系统中，一组为了完成特定功能的SQL 语句集，存储在数据库中，经过第一次编译后再次调用不需要再次编译，用户通过指定存储过程的名字并给出参数（如果该存储过程带有参数）来执行它。存储过程是数据库中的一个重要对象。
示例1
#创建存证文档关联情况下更新所用存储过程
CREATE PROCEDURE evi_doc_refs_eid_deal()
begin
declare pageNum int default 0;
declare totalSize int default 0;
declare pageSize int default 5;
declare totalPage int DEFAULT 0;
declare startIndex int default 0;
select count(*) into totalSize from osv_service_evidence where type != 11 and type !=12 and type !=50 ;
set totalPage = totalSize/pageSize;
while ( pageNum<totalPage-1) do
#对分页的起始下标计算，以便分页查询时使用
set startIndex = pageNum *pageSize;
#开启事务
START TRANSACTION;
#嵌套内部分页查询，通过游标处理分页查询结果记录
begin
#声明变量
declare eviId varchar(50);
declare evidenceEid varchar(50);
declare done int default 0;
declare mark varchar(2);
declare eid_value varchar(50);
declare type_value int default 0;
declare eid_mark varchar(50);
declare num int DEFAULT 0;
#定义分页查询结果的游标
declare i_cur cursor for select id from osv_service_evidence where type !=11 and type !=12 and type !=50 limit startIndex,pageSize;
declare continue handler for sqlstate '09000' set done = 1;
open i_cur;
fetch next from i_cur into eviId;
WHILE (done = 0 ) do
#判断每页中处理数据的下标index
set num = num+1;
select type into type_value from osv_service_evidence where id = eviId;
select e.eid into eid_value from osv_service_evidence e where id = eviId;
if(0 =type_value|null = eid_value) then fetch next from i_cur into eviId;
end if;
#数据处理
if type_value =40 then set mark = 'O'; set eid_mark=concat(mark,eid_value);update evi_doc_refs set docEid = eid_mark where docEviId = eviId;
elseif type_value =11 then set mark = 'S'; set eid_mark=concat(mark,eid_value);update evi_doc_refs set docEid = eid_mark where docEviId = eviId;set done = 0;
end if;
#如果当前页处理的数据已达页记录数值，通过done退出内部循环，进入外部循环
IF num = pageSize THEN set done = 1;
#否则继续当前循环
ELSEIF num !=pageSize THEN set done =0;
fetch next from i_cur into eviId;
END IF;
END WHILE;
#关闭游标
close i_cur;
end ;
COMMIT;
#更新下一次处理的页码，+1
set pageNum = pageNum+1;
end while;
END;
call evi_doc_refs_eid_deal();
示例2
create procedure evi_order_refs_eid_deal()
begin
declare original_eviId varchar(50);
declare evidenceEid varchar(50);
declare done int default 0;
declare mark varchar(2);
declare eid_value varchar(50);
declare type_value int default 0;
declare eid_mark varchar(50);
# declare existence boolean ;
declare cur cursor for select eviId from evi_order_refs where evidenceEid is null order by createTime desc;
##异常处理(触发sql语句失败，执行结束)
declare continue handler for sqlstate '09000' set done = 1;
open cur;
##取出游标值至变量中
fetch next from cur into original_eviId;
repeat
if not done then
select type into type_value from osv_service_evidence where id = original_eviId;
#逻辑判断，如果eviId确实在存证表中无记录，直接忽略该条出证记录
select e.eid into eid_value from osv_service_evidence e where id = original_eviId;
#逻辑判断，如果eviId确实在存证表中无记录，直接忽略该条出证记录
if(0 =type_value|null = eid_value) then fetch next from cur into original_eviId;
end if;
if type_value =40 then set mark = 'O';set eid_mark=concat(mark,eid_value);update evi_order_refs set evidenceEid = eid_mark where eviId = original_eviId;
elseif type_value =11 then set mark = 'S';set eid_mark=concat(mark,eid_value);update evi_order_refs set evidenceEid = eid_mark where eviId = original_eviId;else set done = 0;
end if;
end if;
#if(done = 1) then leave cur;
##重新抓取数据进入循环
fetch next from cur into original_eviId;
##结束循环
until done end repeat;
##关闭游标
close cur;
end ;
或许你在其他博客、文摘中没有找到你想到的答案。即便是从本文中获取到一丝灵感，还是希望您能点赞一次。你的支持是我最大的分享动力。
