我是一个ASP初学者谁可以告诉我下面的代码有什么区别！谢谢了！

set rs=server.CreateObject("ADODB.RecordSet")

rs.Source="select * from product order by productID desc"

rs.Open rs.Source,conn,1,3

*——————————————————————————————

set rs=server.CreateObject("ADODB.RecordSet")

rs.Source="select * from product order by productID desc"

rs.Open rs.Source,conn,1,1

*——————————————————————————————

set rs=server.CreateObject("ADODB.RecordSet")

rs.Source="select * from product order by productID desc"

rs.Open rs.Source,conn,1,2

[459 byte] By [msdn] at [2007-8-14 9:13:07]