怎样利用触发器实现下面的效果，请指教了

怎样利用触发器实现下面的效果，请各位高手指教了
一、建表代码如下：
Create Table BZDM (
 baozhuangdaima varchar(150) not null,
 baozhuangmingcheng varchar(50) not null,
 banbenhao varchar(50) not null,
 long int not null,
 wit int not null,
 high int not null,
 beizhu varchar not null
)

二：实现效果与条件：
条件1.当baozhuangmingcheng为ZX或ZH时，用触发器怎样实现这一效果
baozhuangdaima自动产生为”banbenhao-long-wit-high-banbenhao”的格式，若为其它，则baozhuangdaima=baozhuangmingcheng
条件2.所有新录入的包装代码不能重复，如果有重复，提示此表中有该代码，不能新增，没有重复，则新增进去
条件3.当更改包装名称的时候，当包装名称为ZX,ZH时，产生的格式与条件一一样；
  baozhuangdaima自动产生为”banbenhao-long-wit-high-banbenhao”的格式，若为其它，则baozhuangdaima=baozhuangmingcheng




[解决办法]

SQL code

--trycreate trigger geniuswjt on BZDMinstead of insert,updateasselect @baozhuangmingcheng=baozhuangmingcheng from insertedif @baozhuangmingcheng in ('ZX','ZH')    select @baozhuangdaima=banbenhao+'-'+long+'-'+wit+'-'+high+'-'+banbenhao from insertedelse    set @baozhuangdaima=@baozhuangmingcheng    if exists(select 1 from BZDM where baozhuangdaima=@baozhuangdaima)begin    print '此表中有该代码，不能新增'    returnendif exists(select 1 from inserted) and not exists(select 1 from deleted)    insert into BZDM    select @baozhuangdaima,baozhuangmingcheng,banbenha,[long],wit,high,beizhu from insertedelse if exists(select 1 from inserted) and exists(select 1 from deleted)begin    delete a from BZDM a,deleted b where a.baozhuangdaima=b.baozhuangdaima    insert into BZDM    select @baozhuangdaima,baozhuangmingcheng,banbenha,[long],wit,high,beizhu from insertedend
[解决办法]
SQL code
--声明下变量记得declare @baozhuangmingcheng varchar(100)declare @baozhuangdaima varchar(100)
[解决办法]
探讨

SQL code

--try
create trigger geniuswjt on BZDM
instead of insert,update
as

select @baozhuangmingcheng=baozhuangmingcheng from inserted

if @baozhuangmingcheng in ('ZX','ZH')
    select @b……