>If I want to display Total Price as Qty * Price where Qty comes from one table and Price comes from another, what should I do with my DataSet/TableAdapter?

In my framework data class, I have this condition if we are running against SQL Server:

                ' If we are in SQL Server
                If nBackend = 2 Then

                    ' If we have to make the dataset writable
                    If Not lReadOnly Then
                        loColumn = GetColumn(oDataSet)

                        ' Scan thru all the columns and make them writable
                        For lnCounter = 1 To loColumn.Count
                            lcField = loColumn.Item(lnCounter - 1).ColumnName
                            oDataSet.Tables(0).Columns.Item(lcField).ReadOnly = False
                        Next

                    End If

                End If

Basically, if I define loDataProvider.lReadOnly = True, once the SQL is done, this will make all columns of the dataset table to be writable.

Then, you can scan your dataset results and update any necessary rows.