大虾们帮我看看这个问题，求解释。。。
我们做数据库实验，关于触发器和存储过程的.

题目是：对employee表写一个允许用户一次只删除一条记录的触发器。
我写的代码是：
create trigger delete_one
on employee
for delete
as
begin
declare @delete_count int
select @delete_count=COUNT(*) from deleted
if @delete_count>1
begin
print('一次不能删除多个值！')
rollback
end
end
go


而我看到我一标准答案是：
Create trigger tri_update_emp on employee
For update
As
Declare @oldbir datetime,@newbir datetime,@oldhir datetime,@newhir datetime, @emp_no char(5)
Select @oldbir=birthday,@oldhir=date_hired from deleted
Select @newbir=birthday,@newhir=date_hired from inserted
If((datediff(day,@newbir,@oldhir)>0 or datediff(day,@newbir,@newhir)>0 or datediff(day,@oldbir,@oldhir)>0))
  begin
  If(datediff(year,@newbir,getdate())>=25)
  begin
  If(datediff(year,@newbir,@newhir)>20)
  begin
  Update employee set birthday=@newbir,date_hired=@newhir where emp_no=@emp_no
  end
  Else
  begin 
  Print('年龄间隔不够年,不合常理');
  Rollback transaction
  end
  end
Else
begin
  Update employee set birthday=@newbir,date_hired=@newhir where emp_no=@emp_no
  end
 end
Else
  begin
  Print('时间先后有误,有违常理');
rollback transaction
end
go


里面我想问一下，我觉得只要写不满足条件时系统只要rollback就行，而标准答案还要加上满足条件是该怎样执行的代码，请问有这个必要写满足条件时该怎么执行的代码吗？

------解决方案--------------------

SQL code

create trigger delete_one
on employee
instead of delete
as
begin
declare @delete_count int
select @delete_count=COUNT(*) from deleted
if @delete_count>1
begin
insert employee
select * from deleted
print('一次不能删除多个值！')
rollback
end
end
go

--什么标准答案？不用理会，按照自己的逻辑写，能实现就好了。跳跳大路通罗马