Improving Software

Sub LinkAllTables(Server As String, database As String, OverwriteIfExists As Boolean)
    'Usage Example (link all tables in database "SQLDB" on SQL Server Instance SQO01, overwriting any existing linked tables.
    'linkalltables "SQL01","SQLDB", true

    'This will also update the link if the underlying table definition has been modified.

    Dim rsTableList As New ADODB.Recordset
    Dim sqlTableList As String

    sqlTableList = "SELECT [name] as tablename FROM sysObjects WHERE (type = 'U')"

    rsTableList.Open sqlTableList, BuildSQLConnectionString(Server, database)
    While Not rsTableList.EOF
        If LinkTable(rsTableList("tableName"), Server, database, rsTableList("tableName"), OverwriteIfExists) Then
            Debug.Print "Linked: " & rsTableList("tableName")
        End If
        rsTableList.MoveNext
    Wend

    rsTableList.Close
    Debug.Print "Done."

End Sub

Function LinkTable(LinkedTableAlias As String, Server As String, database As String, SourceTableName As String, OverwriteIfExists As Boolean)
    'This method will also update the link if the underlying table definition has been modified.

    'The overwrite parameter will cause it to re-map/refresh the link for LinktedTable Alias, but only if it was already a linked table.
    ' it will not overwrite an existing query or local table with the name specified in LinkedTableAlias.

    'Links to a SQL Server table without the need to set up a DSN in the ODBC Console.
    Dim dbsCurrent As database
    Dim tdfLinked As TableDef

    ' Open a database to which a linked table can be appended.
    Set dbsCurrent = CurrentDb()

    'Check for and deal with the scenario ofthe table alias already existing
    If TableNameInUse(LinkedTableAlias) Then

        If (Not OverwriteIfExists) Then
            Debug.Print "Can't use name '" + LinkedTableAlias + "' because it would overwrite existing table."
            Exit Function
        End If

        'delete existing table, but only if it is a linked table
        If IsLinkedTable(LinkedTableAlias) Then
            dbsCurrent.TableDefs.Delete LinkedTableAlias
            dbsCurrent.TableDefs.Refresh
        Else
            Debug.Print "Can't use name '" + LinkedTableAlias + "' because it would overwrite an existing query or local table."
            Exit Function
        End If
    End If

    'Create a linked table
    Set tdfLinked = dbsCurrent.CreateTableDef(LinkedTableAlias)
    tdfLinked.SourceTableName = SourceTableName
    tdfLinked.Connect = "ODBC;DRIVER={SQL Server};SERVER=" & Server & ";DATABASE=" & database & ";TRUSTED_CONNECTION=yes;"

    On Error Resume Next
    dbsCurrent.TableDefs.Append tdfLinked
    If (Err.Number = 3626) Then 'too many indexes on source table for Access
            Err.Clear
            On Error GoTo 0

            If LinkTable(LinkedTableAlias, Server, database, "vw" & SourceTableName, OverwriteIfExists) Then
                Debug.Print "Can't link directly to table '" + SourceTableName + "' because it contains too many indexes for Access to handle. Linked to view '" & "vw" & SourceTableName & "' instead."
                LinkTable = True
            Else
                Debug.Print "Can't link table '" + SourceTableName + "' because it contains too many indexes for Access to handle. Create a view named '" & "vw" & SourceTableName & "' that selects all rows/columns from '" & SourceTableName & "' and try again to circumvent this."
                LinkTable = False
            End If
            Exit Function
    End If
    On Error GoTo 0

    tdfLinked.RefreshLink
    LinkTable = True

End Function

Function BuildSQLConnectionString(Server As String, DBName As String) As String
    BuildSQLConnectionString = "Driver={SQL Server};Server=" & Server & ";Database=" & DBName & ";TRUSTED_CONNECTION=yes;"
End Function

Function TableNameInUse(TableName As String) As Boolean
    'check for local tables, linked tables and queries (they all share the same namespace)
    TableNameInUse = DCount("*", "MSYSObjects", "(Type = 4 or type=1 or type=5) AND [Name]='" & TableName & "'") > 0
End Function

Function IsLinkedTable(TableName As String) As Boolean
    IsLinkedTable = DCount("*", "MSYSObjects", "(Type = 4) AND [Name]='" & TableName & "'") > 0
End Function