什么是adovbs.inc

有些ASP网页需要adovbs.inc才能正常显示,请问这些语句的含义
<%
'--------------------------------------------------------------------
' Microsoft ADO
'
' (c) 1996 Microsoft Corporation. All Rights Reserved.
'
'
'
' ADO constants include file for VBScript
'
'--------------------------------------------------------------------

'---- CursorTypeEnum Values ----
Const adOpenForwardOnly = 0
Const adOpenKeyset = 1
Const adOpenDynamic = 2
Const adOpenStatic = 3

'---- CursorOptionEnum Values ----
Const adHoldRecords = &H00000100
Const adMovePrevious = &H00000200
Const adAddNew = &H01000400
Const adDelete = &H01000800
Const adUpdate = &H01008000
Const adBookmark = &H00002000
Const adApproxPosition = &H00004000
Const adUpdateBatch = &H00010000
Const adResync = &H00020000
Const adNotify = &H000400