ASP判断数据是否重复,代码错在哪？该怎么处理

ASP判断数据是否重复,代码错在哪？
代码如下：
set rs=server.createobject("adodb.recordset") 
sql="select * from kybx where bxmc="&request.Form("bxmc")
rs.open sql,conn,1,3
if rs.eof then 

rs.addnew
rs("bxmc") = trim(request.Form("bxmc"))
rs("bxlb") = trim(request.Form("d_position3"))
rs("bxlc") = trim(request.Form("bxlc"))
rs.update
response.Write "<script language=javascript>alert('添加成功！');</script>"
response.write "<meta http-equiv=""refresh"" content=""0;url=kybx.asp"">"

else
Response.write "<script language=javascript>alert('bxmc已经存在!'); history.go(-1);</script>"
end if

response.end
rs.close


set rs=nothing

------解决方案--------------------
set rs=server.createobject("adodb.recordset")
sql="select * from kybx where bxmc="&request.Form("bxmc")
rs.open sql,conn,1,3

if not rs.EOF then

Response.write "已经存在!" 

else

rs.addnew
rs("bxmc") = trim(request.Form("bxmc"))
rs("bxlb") = trim(request.Form("d_position3"))
rs("bxlc") = trim(request.Form("bxlc"))
rs.update
response.Write "添加成功！"
end if

rs.close
set rs=nothing
------解决方案--------------------

VBScript code

sql = "select * from kybx where bxmc='" & request.Form("bxmc") & "'"
rs.open sql,conn,1,3
if rs.eof and rs.bof then
' add new
else
' 已存在
end if

------解决方案--------------------
哪果是根据BMXC这个值判断是否重复，建议在输入BMXC的框中即用AJAX技术判定，免得用户填完后又重新再填，像这种检测放在越前越好。