Preserving linked tables for Access DBs in same fo

问题:

I've got two Access databases that share linked tables. They are deployed together in a directory and accessed via code in a Word form.

How can I make sure that the links are preserved when the two databases are copied (together) to a different folder? Since I'm not "opening" the database, per se (it's being accessed via ADO), I don't know how to write code to refresh the links.

回答1:

Update 14APR2009 I found that the previous answer I gave here was erroneous, so I updated it with new code.

How to proceed

• Copy the code below to a VBA module.

• From code or from the Immediate window in the VBA IDE, simply type:

  RefreshLinksToPath Application.CurrentProject.Path
  

This will now relink all the linked tables to use the directory where your application is located.
It only needs to be done once or whenever you relink or add new tables.
I recommend doing this from code every time you start your application.
You can then move your databases around without problems.

Code

'------------------------------------------------------------'
' Reconnect all linked tables using the given path.          '
' This only needs to be done once after the physical backend '
' has been moved to another location to correctly link to    '
' the moved tables again.                                    '
' If the OnlyForTablesMatching parameter is given, then      '
' each table name is tested against the LIKE operator for a  '
' possible match to this parameter.                          '
' Only matching tables would be changed.                     '
' For instance:                                              '
' RefreshLinksToPath(CurrentProject.Path, "local*")          '
' Would force all tables whose ane starts with 'local' to be '
' relinked to the current application directory.             '
'------------------------------------------------------------'
Public Function RefreshLinksToPath(strNewPath As String, _
    Optional OnlyForTablesMatching As String = "*") As Boolean

    Dim collTbls As New Collection
    Dim i As Integer
    Dim strDBPath As String
    Dim strTbl As String
    Dim strMsg As String
    Dim strDBName As String
    Dim strcon As String
    Dim dbCurr As DAO.Database
    Dim dbLink As DAO.Database
    Dim tdf As TableDef

    Set dbCurr = CurrentDb

    On Local Error GoTo fRefreshLinks_Err

    'First get all linked tables in a collection'
    dbCurr.TableDefs.Refresh
    For Each tdf In dbCurr.TableDefs
        With tdf
            If ((.Attributes And TableDefAttributeEnum.dbAttachedTable) = TableDefAttributeEnum.dbAttachedTable) _
               And (.Name Like OnlyForTablesMatching) Then
                collTbls.Add Item:=.Name & .Connect, key:=.Name
            End If
        End With
    Next
    Set tdf = Nothing

    ' Now link all of them'
    For i = collTbls.count To 1 Step -1
        strcon = collTbls(i)
        ' Get the original name of the linked table '
        strDBPath = Right(strcon, Len(strcon) - (InStr(1, strcon, "DATABASE=") + 8))
        ' Get table name from connection string '
        strTbl = Left$(strcon, InStr(1, strcon, ";") - 1)
        ' Get the name of the linked database '
        strDBName = Right(strDBPath, Len(strDBPath) - InStrRev(strDBPath, "\"))

        ' Reconstruct the full database path with the given path '
        strDBPath = strNewPath & "\" & strDBName

        ' Reconnect '
        Set tdf = dbCurr.TableDefs(strTbl)
        With tdf
            .Connect = ";Database=" & strDBPath
            .RefreshLink
            collTbls.Remove (.Name)
        End With
    Next
    RefreshLinksToPath = True

fRefreshLinks_End:
    Set collTbls = Nothing
    Set tdf = Nothing
    Set dbLink = Nothing
    Set dbCurr = Nothing
    Exit Function

fRefreshLinks_Err:
    RefreshLinksToPath = False
    Select Case Err
        Case 3059:

        Case Else:
            strMsg = "Error Information..." & vbCrLf & vbCrLf
            strMsg = strMsg & "Function: fRefreshLinks" & vbCrLf
            strMsg = strMsg & "Description: " & Err.Description & vbCrLf
            strMsg = strMsg & "Error #: " & Format$(Err.Number) & vbCrLf
            MsgBox strMsg
            Resume fRefreshLinks_End
    End Select
End Function

This code is adapted from this source: http://www.mvps.org/access/tables/tbl0009.htm.
I removed all dependency on other functions to make it self-contained, that's why it's a bit longer than it should.

回答2:

Are you referring to updating the links within your Word form, or the linked table links between your Access databases?

For the former, the best way that I know is to keep your connection string(s) at the Module level within your Word document/VBA project and make them const strings. Then when setting the connection string for your ADO Connection objects, pass it the relative connection string const.

For the latter, I would be tempted to use a relative path in the connection string to data within each Access database to the other. For example,

Dim connectionString as String

connectionString = ";DATABASE=" & CurrentProject.Path & "\[Database Name Here].mdb"

if as you say, the databases are copied together to a different folder (I'm assuming into the same folder).

回答3:

Renaud's answer no longer works in Access 2010 with Excel or CSV files.

I have made a few modifications:

• Adapted to the current pattern for the connection string
• Handled the database path differently for Excel files (includes filename) and CSV files (does not include filename)

Here is the code:

Public Function RefreshLinksToPath(strNewPath As String, _
Optional OnlyForTablesMatching As String = "*") As Boolean

Dim collTbls As New Collection
Dim i As Integer
Dim strDBPath As String
Dim strTbl As String
Dim strMsg As String
Dim strDBName As String
Dim strcon As String
Dim dbCurr As DAO.Database
Dim dbLink As DAO.Database
Dim tdf As TableDef

Set dbCurr = CurrentDb

On Local Error GoTo fRefreshLinks_Err

'First get all linked tables in a collection'
dbCurr.TableDefs.Refresh
For Each tdf In dbCurr.TableDefs
    With tdf
        If ((.Attributes And TableDefAttributeEnum.dbAttachedTable) = _
           TableDefAttributeEnum.dbAttachedTable) _
           And (.Name Like OnlyForTablesMatching) Then
            Debug.Print "Name: " & .Name
            Debug.Print "Connect: " & .Connect
            collTbls.Add Item:=.Name & ";" & .Connect, Key:=.Name
        End If
    End With
Next
Set tdf = Nothing

' Now link all of them'
For i = collTbls.Count To 1 Step -1
    strConnRaw = collTbls(i)
    ' Get table name from the full connection string
    strTbl = Left$(strConnRaw, InStr(1, strConnRaw, ";") - 1)
    ' Get original database path
    strDBPath = Right(strConnRaw, Len(strConnRaw) - (InStr(1, strConnRaw, "DATABASE=") + 8))
    ' Get the name of the linked database
    strDBName = Right(strDBPath, Len(strDBPath) - InStrRev(strDBPath, "\"))
    ' Get remainder of connection string
    strConn = Mid(strConnRaw, InStr(1, strConnRaw, ";") + 1, InStr(1, strConnRaw, "DATABASE=") _
                - InStr(1, strConnRaw, ";") - 1)

    ' Reconstruct the full database path with the given path
    ' CSV-Files are not linked with their name!
    If Left(strConn, 4) = "Text" Then
        strDBPath = strNewPath
    Else
        strDBPath = strNewPath & "\" & strDBName
    End If

    ' Reconnect '
    Set tdf = dbCurr.TableDefs(strTbl)
    With tdf
        .Connect = strConn & "Database=" & strDBPath
        .RefreshLink
        collTbls.Remove (.Name)
    End With
Next
RefreshLinksToPath = True

fRefreshLinks_End:
    Set collTbls = Nothing
    Set tdf = Nothing
    Set dbLink = Nothing
    Set dbCurr = Nothing
    Exit Function

fRefreshLinks_Err:
    RefreshLinksToPath = False
    Select Case Err
        Case 3059:

        Case Else:
            strMsg = "Error Information..." & vbCrLf & vbCrLf
            strMsg = strMsg & "Function: fRefreshLinks" & vbCrLf
            strMsg = strMsg & "Description: " & Err.Description & vbCrLf
            strMsg = strMsg & "Error #: " & Format$(Err.Number) & vbCrLf
            MsgBox strMsg
            Resume fRefreshLinks_End
    End Select
End Function

回答4:

I am unfortunately still on Access 2007. I started with one of the code blocks above which was not working for me. Having less access vba power I simplified it to only the first loop which gets the table paths and updates it in place. The next guy running into this can comment or update.

Option Compare Database

'------------------------------------------------------------'
' Reconnect all linked tables using the given path.          '
' This only needs to be done once after the physical backend '
' has been moved to another location to correctly link to    '
' the moved tables again.                                    '
' If the OnlyForTablesMatching parameter is given, then      '
' each table name is tested against the LIKE operator for a  '
' possible match to this parameter.                          '
' Only matching tables would be changed.                     '
' For instance:                                              '
' RefreshLinksToPath(CurrentProject.Path, "local*")          '
' Would force all tables whose ane starts with 'local' to be '
' relinked to the current application directory.             '
'
' Immediate window type
' RefreshLinksToPath Application.CurrentProject.Path

'------------------------------------------------------------'
Public Function RefreshLinksToPath(strNewPath As String, _
    Optional OnlyForTablesMatching As String = "*") As Boolean

    Dim strDBPath As String
    'Dim strTbl As String
    'Dim strMsg As String
    Dim strDBName As String
    Dim dbCurr As DAO.Database
    Dim dbLink As DAO.Database
    Dim tdf As TableDef

    Set dbCurr = CurrentDb
    Dim strConn As String
    Dim strNewDbConn1 As String
    Dim strNewDbConn2 As String
    Dim strNewDbConn  As String

    '  On Local Error GoTo fRefreshLinks_Err

    'First get all linked tables in a collection'
    dbCurr.TableDefs.Refresh
    For Each tdf In dbCurr.TableDefs
        With tdf
            If ((.Attributes And TableDefAttributeEnum.dbAttachedTable) = TableDefAttributeEnum.dbAttachedTable) _
               And (.Name Like OnlyForTablesMatching) Then

                strConn = tdf.Connect
                strDBPath = Right(strConn, Len(strConn) - (InStr(1, strConn, "DATABASE=") + 8))
                strDBName = Right(strDBPath, Len(strDBPath) - InStrRev(strDBPath, "\"))
                Debug.Print ("===========================")
                Debug.Print (" connect is " + strConn)
                Debug.Print (" DB PAth is " + strDBPath)
                Debug.Print (" DB Name is " + strDBName)

                strDBNewPath = strNewPath & "\" & strDBName
                Debug.Print (" DB NewPath is " + strDBNewPath)

                strNewDbConn1 = Left(strConn, (InStr(1, strConn, "DATABASE=") - 1))
                strNewDbConn2 = "DATABASE=" & strDBNewPath
                strNewDbConn = strNewDbConn1 & strNewDbConn2
                Debug.Print (" DB strNewDbConn is " + strNewDbConn)

                'Change the connect path
                tdf.Connect = strNewDbConn
                tdf.RefreshLink
            End If
        End With
    Next
End Function