怎样利用触发器实现代码替换效果,该如何解决

怎样利用触发器实现代码替换效果
包装信息表 gbaozhuangxingxi
包装ID包装代码数量单位
1ZX-10-10-1-CPT20件/箱
2ZX-10-10-2-CPT30件/箱
3ZX-10-10-3-CPT40件/箱
4ZX-10-10-4-CPT50件/箱



包装计划表Gbaozhuangjihua
包装计划ID包装代码计划数包装ID
1ZX-10-10-1-CPT51
2ZX-10-10-2-CPT62
3ZX-10-10-3-CPT73
4ZX-10-10-4-CPT84

高手些：当修包 计划表(gbaozhuangjihua)中的包装代码时，查询包装信息表(gbaozhuangxingxi)中的包装代码是否存在，若存在，修改当前包装代码，并修改对应的包装信息表中的包装ID查出来替换包装计划表中的包装ID，若不存在，提示包装代码表中不存在相应代码信息，用触发器怎么实现，谢谢大家！

如，我想替换包装信息表中的第三条记录，将ZX-10-10-3-CPT,将他替换成ZX-10-10-2-CPT,它此时就要执行查询包装ZX-10-10-2-CPT 在包装信息表中是否存在，若存在，就替换当前包装代码为ZX-10-10-2-CPT，并将ID改成2,结果如下
包装计划表Gbaozhuangjihua
包装计划ID包装代码计划数包装ID
1ZX-10-10-1-CPT51
2ZX-10-10-2-CPT62
3ZX-10-10-2-CPT72
4ZX-10-10-4-CPT84






[解决办法]

SQL code

create trigger tg_tb on Gbaozhuangjihua    after insert,updateasbeginupdate aset a.包装ID = b.idfrom Gbaozhuangjihua a join gbaozhuangxingxi b on a.包装代码 = b.包装代码where b.id <> a.包装IDend
[解决办法]
SQL code
create table gbaozhuangxingxi (包装ID int, 包装代码 varchar(20), 数量 int, 单位 varchar(10))insert into gbaozhuangxingxiselect 1, 'ZX-10-10-1-CPT', 20, '件/箱' union all select 2, 'ZX-10-10-2-CPT', 30, '件/箱' union all select 3, 'ZX-10-10-3-CPT', 40, '件/箱' union all select 4, 'ZX-10-10-4-CPT', 50, '件/箱'create table Gbaozhuangjihua (包装计划ID int, 包装代码 varchar(20), 计划数 int, 包装ID int)insert into Gbaozhuangjihuaselect 1, 'ZX-10-10-1-CPT', 5, 1 union all select 2, 'ZX-10-10-2-CPT', 6, 2 union all select 3, 'ZX-10-10-3-CPT', 7, 3 union all select 4, 'ZX-10-10-4-CPT', 8, 4 create trigger tr_Gbaozhuangjihua on Gbaozhuangjihuafor updateasbegin if update(包装代码) begin   if exists(select 1 from gbaozhuangxingxi a              inner join inserted b on a.包装代码=b.包装代码)      update a set a.包装ID=             (select a.包装ID from gbaozhuangxingxi a               inner join inserted b on a.包装代码=b.包装代码)      from Gbaozhuangjihua a      inner join inserted b on a.包装计划ID=b.包装计划ID   else   begin      print '包装代码表中不存在相应代码信息.'      rollback tran   end    endend-- 测试更新为 ZX-10-10-2-CPTupdate Gbaozhuangjihua set 包装代码='ZX-10-10-2-CPT' where 包装计划ID=3select * from Gbaozhuangjihua包装计划ID      包装代码            计划数        包装ID----------- -------------------- ----------- -----------1           ZX-10-10-1-CPT       5           12           ZX-10-10-2-CPT       6           23           ZX-10-10-2-CPT       7           24           ZX-10-10-4-CPT       8           4-- 测试更新为不存在的包装代码update Gbaozhuangjihua set 包装代码='abc' where 包装计划ID=3select * from Gbaozhuangjihua包装计划ID      包装代码            计划数        包装ID----------- -------------------- ----------- -----------1           ZX-10-10-1-CPT       5           12           ZX-10-10-2-CPT       6           23           ZX-10-10-2-CPT       7           24           ZX-10-10-4-CPT       8           4
[解决办法]
探讨

兄弟，有一个问题，就是一改这条记录把我gbaozhuangxingxi表中的所有包装ID给改完了，不对啊，我只需改对应这条的包装ID