create table 表A
(年 int, 数量 int)

insert into 表A
select 2012, 132 union all
select 2011, 332 union all
select 1985, 222 union all
select 1984, 332;

-- 建触发器
create trigger tr_表A 
on 表A 
for update,delete,insert
as
begin
 if exists(select 1 from inserted where 年<2011)
    or exists(select 1 from deleted where 年<2011)
 begin
   rollback transaction;
   raiserror(N'禁止update,insert,delete 2011年前的数量.',10,1);
 end  
end

--> 测试update,insert,delete 2011年前的数量

update 表A set 数量=611 where 年=1985
/*
禁止update,insert,delete 2011年前的数量.
Msg 3609, Level 16, State 1, Line 1
The transaction ended in the trigger. The batch has been aborted.
*/

insert into 表A select 1981,132
/*
禁止update,insert,delete 2011年前的数量.
Msg 3609, Level 16, State 1, Line 1
The transaction ended in the trigger. The batch has been aborted.
*/

delete from 表A where 年=1984
/*
禁止update,insert,delete 2011年前的数量.
Msg 3609, Level 16, State 1, Line 1
The transaction ended in the trigger. The batch has been aborted.
*/

--> 表数据未变更
select * from 表A
/*
年           数量
----------- -----------
2012        132
2011        332
1985        222
1984        332

(4 row(s) affected)
*/