找不到要更新的資料列。最後讀取的值已被變更
現在表:
合同主表：Contract(ContractID,CompanyID,ContractName.ContractVolume)
公司資訊表：Company(CompanyID,CompanyName,Remark)
ContractID,CompanyID分別為主鍵．
要完成的任務：
當更改公司號（Companyid)後，合同中對應公司的公司號也隨著變更
ＳＱＬ代碼如下：
Create   Trigger     [Company_Update]     on     Company
For   Update
As
Begin
Declare   @i_CompanyID   Varchar(20),@d_CompanyID   Varchar(20)

Declare   Company_InsertCursor   Cursor
For
Select   CompanyID   From   Inserted

Declare   Company_DeleteCursor   Cursor
For
Select   Companyid   From   Deleted

Open   Company_InsertCursor
Open   Company_DeleteCursor

Fetch   Next   From   Company_InsertCursor  
Into   @i_CompanyID

Fetch   Next   From   Company_DeleteCursor
Into   @d_CompanyID

While   @@Fetch_Status=0
Begin

IF   @i_CompanyID <> @d_Companyid
Begin
Update   Contract
Set   CompanyID=@i_CompanyID
Where   CompanyID=@d_CompanyID
End

Fetch   Next   From   Company_InsertCursor  
Into   @i_CompanyID

Fetch   Next   From   Company_DeleteCursor
Into   @d_CompanyID

End
Close   Company_InsertCursor
Deallocate   Company_InsertCursor
Close   Company_DeleteCursor
Deallocate   Company_DeleteCursor
End
但是更改公司資訊表中的公司號後，總是出現：＂找不到要更新的資料列。最後讀取的值已被變更＂這個問題，為什麽呀？要如何做才不會這樣?請高手指點，不勝感激，


------解决方案--------------------
現在表:
合同主表：Contract(ContractID,CompanyID,ContractName.ContractVolume)
公司資訊表：Company(CompanyID,CompanyName,Remark)
ContractID,CompanyID分別為主鍵．
要完成的任務：
當更改公司號（Companyid)後，合同中對應公司的公司號也隨著變更

update A
set CompanyID=B.CompanyID
from Contract A
inner join Company B
on A.CompanyID=B.CompanyID
where B.CompanyID= 'c00001 '
------解决方案--------------------
不要使用触发器,用外键约束来实现对Contract表CompanyID的更新
------解决方案--------------------
代码改成:
Create Trigger [Company_Update] on Company
For Update
As
set nocount on
Begin
Declare @i_CompanyID Varchar(20),@d_CompanyID Varchar(20)

Declare Company_InsertCursor Cursor
For
Select CompanyID From Inserted

Declare Company_DeleteCursor Cursor
For
Select Companyid From Deleted

Open Company_InsertCursor
Open Company_DeleteCursor

Fetch Next From Company_InsertCursor
Into @i_CompanyID

Fetch Next From Company_DeleteCursor
Into @d_CompanyID

While @@Fetch_Status=0
Begin

IF @i_CompanyID <> @d_Companyid
Begin
Update Contract
Set CompanyID=@i_CompanyID
Where CompanyID=@d_CompanyID
End

Fetch Next From Company_InsertCursor
Into @i_CompanyID

Fetch Next From Company_DeleteCursor
Into @d_CompanyID

End
Close Company_InsertCursor
Deallocate Company_InsertCursor
Close Company_DeleteCursor
Deallocate Company_DeleteCursor
End
set nocount off