sample vb resolver(

介绍了数据库方面的基础知识

作者：怡红公子
email: [e-mail]
日期：2001-6-30 10:37:03
SQL 2000中合并复制有很强大的冲突解决方案，其中除了SQL2k自己定义的以外，还可以使用VB/VC来自己编写冲突解决方案。（参见ppt文档）
下面是使用VB的一个Demo，ppt文档中有提到的。
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'=====================================================================
'  This file is part of the Microsoft SQL Server replication Code Samples.
'
'  Copyright (C) 1999-2001 Microsoft Corporation.  All rights reserved.
'
' This source code is intended only as a supplement to Microsoft
' Development Tools and/or on-line documentation.  See these other
' materials for detailed information regarding Microsoft code samples.
'
' THIS CODE AND INFORMATION ARE PROVIDED "AS IS" WITHOUT WARRANTY OF ANY
' KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
' IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
' PARTICULAR PURPOSE.
'=====================================================================

'---------------------------------------------------
'   IVBCustomResolver_GetHandledStates
'   This method returns the set of states that are
'   handled by the custom resolver - This resolver
'   handles update conflicts only.
'---------------------------------------------------
Public Sub IVBCustomResolver_GetHandledStates(ByRef pResolverBm As Long)
    Dim rct As SQLResolver.REPOLE_CHANGE_TYPE
    
    rct = REPOLEChange_SubscriberUpdate_ConflictColTrack Or _
            REPOLEChange_PublisherUpdate_ConflictColTrack Or _
            REPOLEChange_PublisherUpdate_ConflictNoColTrack Or _
            REPOLEChange_PublisherUpdate_ConflictColTrack
    pResolverBm = rct
End Sub


'---------------------------------------------------
'   IVBCustomResolver_Reconcile
'   This method is invoked by the merge process whenever
'   an update conflict has been encountered.
'---------------------------------------------------
Public Sub IVBCustomResolver_Reconcile
(ByVal rrc As IReplRowChange, 
ByVal dwFlags As Long, 
ByVal rrcSugg As IReplRowChange)  


IVBCustomResolver_ComputeMinimumValue:
    ' Get the Publisher's value for the resolver column into PublisherData
    ' Get the Subscriber' value for the resolver column into SubscriberData

    If SrcIsPublisher Then
        rrc.GetSourceColumnValue iColumn, PublisherData, 0&, 0&
        rrc.GetDestinationColumnValue iColumn, SubscriberData, 0&, 0&
    Else
        rrc.GetSourceColumnValue iColumn, SubscriberData, 0&, 0&
        rrc.GetDestinationColumnValue iColumn, PublisherData, 0&, 0&
    End If
    
    ' Compute the minimum value and use that to chose the winner as the
    ' source or the destination. If the Publisher and Subscriber data
    ' values match choose the winner based on priorities.
    
    ' Case 1: PublisherData < SubscriberData
    If PublisherData < SubscriberData Then
        ResolvedData = PublisherData
        If SrcIsPublisher Then
            WinnerPriority = REPOLEPriority_Source
        Else
            WinnerPriority = REPOLEPriority_Destination
        End If
    ' Case 2: PublisherData > SubscriberData
    ElseIf SubscriberData < PublisherData Then
        ResolvedData = SubscriberData
        If DestIsPublisher Then
            WinnerPriority = REPOLEPriority_Source
        Else
            WinnerPriority = REPOLEPriority_Destination
        End If
    ' Case 3: PublisherData = SubscriberData
    Else
        ResolvedData = PublisherData
        rrc.GetPriorityWinner WinnerPriority
    End If

    ' If the winner is not the source just exit - the winner will be chosen
    ' on the next phase
    If WinnerPriority <> REPOLEPriority_Source Then
        GoTo IVBCustomResolver_Reconcile_Exit
    Else
        ' Log the destination's update as a conflict loser and
        ' Propagate the source's update as the winning value.
        rrc.LogConflict False, REPOLEConflict_UpdateConflict, True
        rrc.CopyRowFromSource
    End If
    
    ' Display an infomational message indicating the resolution.
    Select Case ChangeType
        Case REPOLEChange_SubscriberUpdate_ConflictColTrack, _
                REPOLEChange_PublisherUpdate_ConflictColTrack, _
                REPOLEChange_SubscriberUpdate_ConflictNoColTrack, _
                REPOLEChange_PublisherUpdate_ConflictNoColTrack
            stMessage = "The column " & stResolverColumn & " was updated at the Publisher (" & _
                stPublisher & ":" & stPublisherDB & ") to value : " & CStr(PublisherData) & _
                " and the Subscriber (" & stSubscriber & ":" & stSubscriberDB & ") to value : " & CStr(SubscriberData) & _
                ". The resolver chose the row with column value " & CStr(ResolvedData) & " as the winner."
        Case Else
            stMessage = msgUnhandledConflict
    End Select