Private Sub Abrechnungsdatei_erstellen()
       Dim _cnML As New OdbcConnection( _
         "FILEDSN=c:\ml\ml_dbase;DefaultDir=c:\ML;")
       Try
            Dim _daSA1 As New OdbcDataAdapter("select * from patdat", _cnML)
            Dim _daSA2 As New OdbcDataAdapter("select * from ekg", _cnML)
            Dim _ds As New DataSet
            _daSA1.Fill(_ds, "SA1")
            _daSA2.Fill(_ds, "SA2")
            _ds.Tables("SA1").Constraints.Add(new UniqueConstraint( _
              "PateientenKey", new DataColumn[] { _ds.Tables("SA1").Columns( _
              "PATNR")}, true));
            _ds.Relations.Add(New DataRelation("relSA", _ds.Tables( _
            "SA1").Columns("PATNR"), _ds.Tables("SA2").Columns("PATNR")))
            _ds.Relations.Item(0).Nested = True
            _ds.EnforceConstraints = true 
            _cnML.Close()
            DataGrid1.DataSource = _ds
            DataGrid1.DataMember = _ds.Tables("SA1").ToString
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
End Sub