唐朝杨贵妃是哪个皇帝:这段"增加产品"代码如何改成"修改产品信息"?

<% if request.querystring("action")="add" then
if trim(request.form("product_name"))="" then
response.Write "<script language=javascript>alert('产品名称不能为空！');window.location.href='add_product.asp';</script>"
response.end
end if
set rs=server.createobject("adodb.recordset")
sql="select * from product_info "
rs.open sql,conn,1,3
rs.addnew
rs("sort_id")=trim(request.form("sort_id"))
rs("product_name")=trim(request.form("product_name"))
rs("product_sort")=trim(request.form("product_sort"))
rs("small_img")=trim(request.form("small_img"))
rs("big_img")=trim(request.form("big_img"))
if trim(request.form("tuijian"))<>"" then rs("tuijian")=trim(request.form("tuijian"))
if trim(request.form("pass"))<>"" then rs("pass")=trim(request.form("pass"))
rs("sub_person")=trim(request.form("sub_person"))
if trim(request.form("sx"))<>"" then rs("sx")=trim(request.form("sx"))
rs("product_info")=trim(request.form("product_info"))
rs.update
response.Write "<script language=javascript>alert('添加产品成功！');window.location.href='add_product.asp';</script>"
rs.close
set rs=nothing
conn.close
set conn=nothing
end if
%>