遇到"行集不支持反向提取"时该怎么办

[currentopen]

在调用ACCESS数据库时,执行下列代码:
DbPath = Server.MapPath("../temp.mdb")
Set DataConn = Server.CreateObject("ADODB.Connection")
DataConn.Open "driver={Microsoft Access Driver (*.mdb)};dbq="& DbPath
Set DataCmd = Server.CreateObject("ADODB.Command")
DataCmd.CommandText = "select * from usertab"
Set DataCmd.ActiveConnection = DataConn
Set rs_main = Server.CreateObject("ADODB.Recordset")
Set rs_main = DataCmd.execute
rs_main.MoveLast
response.write (rs_main.RecordCount)
出现提示"行集不支持反向提取",我该如何处理,请高手指点.多谢!

[changechange]

rs.CursorLocation = adUseClient


DbPath = Server.MapPath("../temp.mdb")
Set DataConn = Server.CreateObject("ADODB.Connection")
DataConn.Open "driver={Microsoft Access Driver (*.mdb)};dbq="& DbPath
'上述驱动用错，应该用 JET DB
Set DataCmd = Server.CreateObject("ADODB.Command")
'根本没必要用 COMMAND 对象
DataCmd.CommandText = "select * from usertab"
Set DataCmd.ActiveConnection = DataConn
Set rs_main = Server.CreateObject("ADODB.Recordset")
Set rs_main = DataCmd.execute
'为什么不用OPEN ?
rs_main.MoveLast
response.write (rs_main.RecordCount)














DbPath = Server.MapPath("../temp.mdb")
Set DataConn = Server.CreateObject("ADODB.Connection")
dim rs
set rs=server.createobject("adodb.recordset")
DataConn.Open "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & DbPath & ";User ID=admin;Password=;Jet OLEDB:Database Password="
rs.CursorLocation = 3
rs.open "select * from usertab",dataconn,2,3
response.write (rs.RecordCount)