怎样用触发器对SQL Server进行数据备份

一个用于插入数据，test3
另一个作为备份，test3_bak
create table test3(id int primary key not null 
identity(1,1),uname varchar(20),uage int);
create table test3_bak(id int primary key not 
null identity(1,1),bid int,uname varchar(20),
uage int,active char(1));

alter trigger test3_bak_insert_update
on test3
for insert,update
as
 declare @id int
 declare @uname varchar(20)
 declare @uage int
begin
 select @id=id,@uname=uname,@uage=uage from inserted
 if @id<>0
 begin
  update test3_bak set active='0' where bid=@id
  insert into test3_bak(bid,uname,uage,active)
   values(@id,@uname,@uage,'1') 
 end
end

insert into test3(uname,uage) values('FLB',20)
insert into test3(uname,uage) values('FLB1',21)
insert into test3(uname,uage) values('FLB2',22)

update test3 set uage=100 where id=27
delete from test3 where id=20

select * from test3
select * from test3_bak