Hi There!

I have a question of Combining Multipe Related Tables.
Here is the code:

'Private ds As DataSet
Private cn As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0; Password="""";User ID=Admin;Data Source=C:\wwwroot\db\universal.mdb;.....)

Private Sub btnFill_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnFill.Click

        Dim da As New OleDbDataAdapter()
        grd.DataSource = Nothing
        Dim ds As DataSet = New DataSet()


        da.SelectCommand = New OleDbCommand()
        da.SelectCommand.Connection = cn
        da.SelectCommand.CommandType = CommandType.Text
        da.SelectCommand.CommandText = "select * from invoice ; select * from order"

        da.TableMappings.Add("Table", "Invoice")
        da.TableMappings.Add("Table1", "Order")

        da.Fill(ds)

        'ds.Relations.Add("Invo_order", ds.Tables("invoice").Columns("oid"), ds.Tables("order").Columns("oid"))

        grd.DataSource = ds

    End Sub

I have a error message when I press "Fill" button:

"An unhandled exception of type 'System.Data.OleDb.OleDbException' occurred in system.data.dll"

and point out the code "da.Fill(ds)" cannot run.

Can anybody point out the error of these code, I have no idea of this. Exhausted!!

Thank you!