How should I pass data between classes and application layers?

Question

For example, if I am creating a 3 layer application (data / business / UI) and the data layer is grabbing single or multiple records. Do I convert everything from data layer in

Answer 1

The application that I'm working on now is fairly old (in .NET terms) and uses strongly typed datasets to pass data between the data layer and the business layer. In the business layer, the data in the datasets is manually "or mapped" to business objects before being passed to the front end.

This is probably not a popular design decision though because strongly typed dataset were always somewhat controversial.