How To Link and Refresh Linked Jet Tables Using ADOX

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Summary

You can update the connection information for a linked table by using the Data Access Objects (DAO) RefreshLink method. This article describes another way to do this with ActiveX Data Objects (ADO) version 2.1 and later by using the Tables collection exposed by the ADO Extensibility model (ADOX).

More Information

  1. In Microsoft Visual Basic, create a new Standard EXE project. Form1 is added to the project by default.
  2. On the Project menu, click References. From the list of available components, select Microsoft ActiveX Data Objects 2.1 Library and Microsoft ADO Ext. 2.1 for DDL and Security.
  3. Place two CommandButton controls on Form1: cmdRefreshLink and cmdCreateLinkedTable.
  4. Paste the following code in the Declarations section of Form1:
    Option Explicit

    Dim cn As ADODB.Connection

    Private Sub Form_Load()
    Set cn = New ADODB.Connection
    cn.Open "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D:\Db1.mdb"
    End Sub

    Private Sub cmdCreateLinkedTable_Click()
    Dim cat As ADOX.Catalog
    Dim tbl As ADOX.Table

    Set cat = New ADOX.Catalog
    Set tbl = New ADOX.Table

    ' Open the catalog.
    cat.ActiveConnection = cn

    ' Create the new Table.
    tbl.Name = "Linked_Employees"
    Set tbl.ParentCatalog = cat

    ' Set the properties to create the link.
    tbl.Properties("Jet OLEDB:Link Datasource") = "D:\nwind.mdb"
    tbl.Properties("Jet OLEDB:Remote Table Name") = "Employees"
    tbl.Properties("Jet OLEDB:Create Link") = True

    ' Append the table to the Tables collection.
    cat.Tables.Append tbl
    Set cat = Nothing
    End Sub

    Private Sub cmdRefreshLink_Click()
    Dim cat As ADOX.Catalog
    Dim tbl As ADOX.Table

    Set cat = New ADOX.Catalog
    Set tbl = New ADOX.Table

    ' Open the catalog.
    cat.ActiveConnection = cn
    For Each tbl In cat.Tables
    If tbl.Type = "LINK" And tbl.Name = "Linked_Employees" Then
    tbl.Properties("Jet OLEDB:Link Datasource") = "D:\OtherSource.mdb"
    End If
    Next
    End Sub
  5. Modify the code in the Form_Load() event to point the connection string to a valid Database in the cn.Open method.
  6. Modify the code in the cmdCreateLinkedTable_Click() event to point the connection string to the Northwind sample database in the tbl.Properties("Jet OLEDB:Link Datasource") assignment.
  7. Modify the code in the cmdRefreshLink_Click() event to point the tbl.Properties("Jet OLEDB:Link Datasource") assignment to another valid location.
  8. Run the project.
The cmdCreateLinkedTable() procedure creates a linked table, Linked_Employees, from the Northwind sample database Employees table. The cmdRefreshLink() procedure refreshes the linked tables with a new database location.

References

240222 How To Use ADO to Refresh/Create Linked Table for Password Secured Jet 4.0 Database
 
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ID članka: 230588 - posljednja izmjena: 23. sij 2013. - verzija: 1

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