Dim myCat As ADOX.Catalog
Dim CN As ADODB.Connection
 
Set CN = New Connection
With CN
    .Provider = "Microsoft.Jet.OLEDB.4.0"
    .CursorLocation = adUseClient
    .Properties("Data Source") = "C:TempMyDataBase.mdb"
    .Open
End With
Set myCat = New ADOX.Catalog
Set myCat.ActiveConnection = CN
myCat.Tables("myTable").Columns("MyColoumn").Attributes = adColNullable
CN.Close
Set myCat = Nothing
Set CN = Nothing