In the future you may want to be just a little bit more specific about your project such as the type of DB etc. But, here is a very easy method of checking records in an Access DB to see if they already exist:
<%
Dim rsGET
Set rsGET = Server.CreateObject("ADODB.Recordset")
rsGET.ActiveConnection = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\myDatabase.mdb"
rsGET.Source = "Select myRecord from myTable where myRecord = " + formValue
rsGET.CursorType = 0
rsGET.CursorLocation = 2
rsGET.LockType = 1
rsGET.Open()
If rsGET.BOF OR rsGET.EOF Then
' NO MATCHING RECORDS FOUND CODE
Else
' FOUND MATCHING RECORDS CODE
End If
%>
' Other html code here
<%
' Destroy and close the db connection
rsGET.Close()
Set rsGET = Nothing
%>
rsGET.BOF and rsGET.EOF stand for Beginning of File and End of File respectively.
To the server, if it reaches either end of the DB and has not found anything then it will fire the 'NO MATCHING RECORDS code. If it does find the record in question it will fire the FOUND MATCHING RECORD codeafter the Else statement.
Hope it helps!