如何便得文件夹中文件与数据表记录中保持一致？谢谢各位了

下面代码是读取文件夹中文件并写入数据表中
但现在存在一个问题如何确保与数据表记录中保持一致，也就是当写入数据表时，若数据表记录已经存在则不添加，否则将文件名添加到数据表中，若文件不存在而数据表中有记录则清除记录该，总之就是“文件夹中文件与数据表记录中保持一致”~！

<!-- #include file="conn.asp" -->
<!-- #include file="../yhqx.asp" -->
<%
  TruePath=Server.MapPath("htxt_bb")  
  set fso=CreateObject("Scripting.FileSystemObject")  
  Set theFolder=fso.GetFolder(TruePath)  
  i = 1  
  For Each theFile In theFolder.Files  
  'Response.write("第"&i&"个<br>")  
  Response.write(""&i&"、"&theFile.Name&"<br>")  
  i = i+1  
  Next  
  For Each theFile In theFolder.Files  
dim path
path=TheFile.Name
  sql = "insert into htxt_bb(ht_bb_1)values('"&path&"')"  
  Conn.execute(sql)  
  Next
%>

htnow=now
For Each theFile In theFolder.Files  
dim path
path=TheFile.Name
set rs=server.createobject("adodb.recordset")
sqltext1="select * from htxt_bb where ht_bb_1='"&path&"' "
rs.open sqltext1,conn,1,1
If rs.recordcount<=0 Then
  sql = "insert into htxt_bb(ht_bb_1,ctime)values('"&path&"','"&htnow&"')"  
  Conn.execute(sql)
else
  sql = "update htxt_bb set ctime='"&htnow&"' where ht_bb_1='"&path&"'"  
  Conn.execute(sql)
end if  
Next
sql = "delete htxt_bb where ctime<>'"&htnow&"' "  
Conn.execute(sql)