One way to work around this behavior is to programmatically refresh the links by using ActiveX Extensibility Objects (ADOX) after the run-time application has been installed. The following is an illustration of how to implement this technique. Please note that this article assumes that the back-end databases are stored in subfolders under the front-end database.
- Make sure you have the latest version of the Microsoft Data Access Components (MDAC) installed on your computer. MDAC can be found at the following Microsoft Web site:
- Set a reference to Microsoft ADO Ext 2.5 (or later) for DDL and Security.
- Create a new database and name it FrontEnd.mdb.
- Import the Customers and Employees forms from the sample database Northwind.mdb into FrontEnd.mdb.
- Create a new database and subfolder under the folder where the FrontEnd.mdb file is located, for example, Folder1\Backend1.mdb.
- Import the Customer table from Northwind.mdb into Backend1.mdb.
- Create a new database and subfolder under the folder where the FrontEnd.mdb file is located, for example, Folder2\Backend2.mdb.
- Import the Employee table from Northwind.mdb into Backend2.mdb.
- Open the FrontEnd.mdb database and create a new module. In the module, paste in the following code:This function checks the first linked table in the database to determine if the links are valid. If the links are not valid, the function searches for the database and refreshes the links.
Option Compare Database
Private Declare Function apiSearchTreeForFile Lib "ImageHlp.dll" Alias _
"SearchTreeForFile" (ByVal lpRoot As String, ByVal lpInPath _
As String, ByVal lpOutPath As String) As Long
On Error GoTo ErrorHandler
Dim objCat As New ADOX.Catalog 'Define the ADOX Catalog Object
Dim objTbl As ADOX.Table 'Define the ADOX Table Object
Dim strSearchFolder As String 'Folder to Search in.
Dim strFilename As String 'Db Name of the Linked Table
Dim strFullName As String 'Path & DB Name of the Linked Table.
Dim strSearchFile As String 'The new path of the database.
Dim blnTablesNotLinked As Boolean 'Determines if links are valid
'Open the catalog
objCat.ActiveConnection = CurrentProject.Connection
'Loop through the table collection and refresh the linked tables.
For Each objTbl In objCat.Tables
' Check to make sure the table is a linked table.
If objTbl.Type = "LINK" Then
strFullName = objTbl.Properties("Jet OLEDB:Link Datasource")
strFilename = Mid(strFullName, InStrRev(strFullName, "\", _
Len(strFullName)) + 1, Len(strFullName))
strSearchFolder = CurrentProject.Path
'The following line of code attempts to refresh the link.
'If the source cannot be found an error is generated.
'Please note that this code only checks one table to determine
'whether or not the links are valid.
objTbl.Properties("Jet OLEDB:Link Datasource") = strFullName
If blnTablesNotLinked = False Then
'Set the search path to the path of the current project.
'The assumption is that the linked tables are located in subfolders.
strSearchFile = SearchFile(strFilename, strSearchFolder)
objTbl.Properties("Jet OLEDB:Link Datasource") = strSearchFile
MsgBox "The links were successfully refreshed!!! "
Select Case Err.Number
blnTablesNotLinked = True
MsgBox Err.Description & " " & Err.Number
Function SearchFile(ByVal strFilename As String, _
ByVal strSearchPath As String) As String
'Search the folder for first occurrence of the source databases.
Dim strBuffer As String
Dim lngResult As Long
SearchFile = ""
strBuffer = String$(1024, 0)
lngResult = apiSearchTreeForFile(strSearchPath, strFilename, strBuffer)
If lngResult <> 0 Then
If InStr(strBuffer, vbNullChar) > 0 Then
SearchFile = Left$(strBuffer, InStr(strBuffer, vbNullChar) - 1)
- Create a new macro with the following properties, and name it AutoExec:
Note that you can also call this function in the Open event of a hidden Startup Form.
Function Name: RefreshLinks()
Form Name: Customers
Form Name: Employees
- Build the package for the run-time application. Remember to add "Folder1" and "Folder2" to the respective installation locations.
For Access 2007 and for Access 2003, add the back-end files in the "Additional Files" section, and then provide respective folder names "Folder1" and "Folder2" in the Install Subfolder column.
For Access 2002 and for Access 2000, add "$(AppPath)\Folder1\" and "$(AppPath)\Folder2\" to the respective installation locations on the Install Location page.
- Deploy the run-time application.
Artikelnummer: 291264 – Letzte Überarbeitung: 30.10.2008 – Revision: 1