帮忙改正个触发器，谢谢！
CREATE   TABLE   [HMNUM]   (
[HMNUM]   [int]   NULL   DEFAULT   (0),
--   [HMNUMSTRING]   =   [HMNUM]   &   ".00 "   eg:   HMNUM   =   6543,   HMNUMSTRING   =6543.00
                [HMNUMSTRING]   [nvarchar]   (20)   NULL   ,
[ProductIDFactory]   [nvarchar]   (50)   NULL   ,
[FACTORY]   [nvarchar]   (50)   NULL   ,
[DATE]   [datetime]   NULL   ,
CONSTRAINT   [CK   HMNUM   ProductIDFactory]   CHECK   ([ProductIDFactory] <>   '/ '   and  

[ProductIDFactory]   <>   '. ')
)   ON   [PRIMARY]
GO

CREATE   TABLE   [Product]   (
[ProductID]   [int]     NOT   NULL,
[ProductIDFactory]   [nvarchar]   (50),
[Colour]   [nvarchar]   (110)   ,
[PL]   [float]   ,
[PW]   [float]     ,
[PH]   [float]     ,
[Weight]   [float]  
)  
GO

现在要写个触发器，当Insert   [HMNUM]([ProductIDFactory],[FACTORY])   values

( 'TestProductID01 ', 'TestFactory ')时，要实现

1.　[HMNUM]=max([HMNUM])+1
2.　[HMNUMSTRING]   =   [HMNUM]   &   ".00 "   eg:   HMNUM   =   6543,   HMNUMSTRING   =6543.00
3.　[DATE]=getdate()

而且要判断[ProductIDFactory]之前不在[HMNUM]、[Product]两个表中


以下是我自己写的
好像错误很多。。。
请帮忙指正，谢谢！！！

create   trigger   tr_InsertHMNum  
on   HMNum
instead   of   insert

as
declare   @HMNum   int
declare   @HMNumString   nvarchar(20)

select   @HMNum=max(A.[HMNUM]),@HMNumString=cast(@HMNum   as   nvarchar(20))   &  

'.00 ',b.ProductIDFactory,b.Factory
from   HMNum   as   A,   inserted   as   B
where   A.[ProductIDFactory]=B.[ProductIDFactory]


IF   not   exists   (select   *   from   HMNum   a   where   exists(select   1   from   inserted   where  

ProductIDFactory=a.ProductIDFactory))  
      and   not   exists(select   *   from   Product   b   where   exists(select   1   from   inserted   where  

ProductIDFactory=b.ProductIDFactory))
begin
insert   HMNum   values(@HMNum,@HMNumString, 'ProductIDFactory ', 'Factory ',getdate())
end  
go


------解决方案--------------------
create trigger tr_InsertHMNum
on HMNum
instead of insert

as
declare @HMNum int
declare @HMNumString nvarchar(20)
SET XACT_ABORT ON
BEGIN TRAN

SELECT @HMNUM=max(HMNUM)+1 from (SELECT max(HMNUM) FROM HMNum UNION ALL SELECT 0)TB
SELECT @HMNumString=cast(@HMNum as nvarchar(20)) & '.00 '

IF not exists (select * from HMNum a where exists(select 1 from inserted C where C.ProductIDFactory=a.ProductIDFactory))
and not exists(select * from Product b where exists(select 1 from inserted C where C.ProductIDFactory=b.ProductIDFactory))
begin
insert HMNum SELECT @HMNum,@HMNumString,ProductIDFactory,Factory,getdate() FROM INSERTED
end
CO