请教一个修改已插入表中的identity值的记录的方法

[iamme81]

现有表a结构
create table a(a int identity(1,1),b int)
insert a values(1)
insert a values(1)
.
.
.

表中的记录为
a b
1 1
2 1
现要将a为2的记录修改为a等于2000，而a为identity属性的字段，一般情况下不允许修改，请问在不变动表结构的情况下有没有办法暂时去掉限制使可以修改此值。

[水族杰纶]

--你可以增加一列
alter table a
add id int 
go
update a set id=a*1
go

[jia_guijun]

begin tran
set identity_insert t on
insert t(a,b) select 2000,b from t where a=2
delete t where a=2
set identity_insert t off
commit

[jia_guijun]

begin tran
	set identity_insert a on
	insert a(aid,aname) select 2000,aname from a where aid=2
	delete a where aid=2
	set identity_insert a off
commit

[jia_guijun]

先装自增标识关闭，然后复制一条记录，再删除原来记录，开启自增标识

begin tran
	set identity_insert t on
	insert t(a,b) select 2000,b from t where a=2
	delete t where a=2
	set identity_insert t off
commit