sql 事务处理 与 try catch

begin transaction tr
   declare @error int;
   set @error=0;
   select * from Car_Brand
   set @error=@error+@@ERROR
   select 1/0
   set @error=@error+@@ERROR
   select * from AREA
   set @error=@error+@@ERROR
   print 'i have executed!'
   set @error=@error+@@ERROR
   
   print '@@error:'+cast(@error as varchar(50))
   if(@error<>0)
     begin
      print 'executed failed';
      rollback transaction tr
     end
   else    
     begin
      print 'executed success';
      commit transaction tr
     end

begin  try
begin transaction tr

   select * from Car_Brand
   update car_log set [reason]='ceshiceshiceshi' where [modelid]=557;
   select 1/0
   print 'i have executed!'
   select * from AREA
   
   
   print 'executed success';
   commit transaction tr
   
   
end try
begin catch
  print 'executed failed';
  rollback transaction tr
end catch