i've been programmer (VB6, .Net, ASP, using COM+ and WEB SERVICE) and i understood when you make this kind of app (3-layers), app is a "slave" of data repository (DB2, SYBASE, INFORMIX, SQLSERVER, EXCEL even MainFrame).

the app retrieves null values .....who cares ?? this languages, all of them, have facilities to manipulate any values (null, date, int, long, etc).