Basically, you wire methods at business layer with operations at presentation layer.
This way you can have absolute strict control over the flow of the program.
To retrieve data from a business object, set the Select Method property with the name of the method that retrieves data.
NET, you can perform data access either programmatically or declaratively with out writing single piece of code.
You can perform all common database related tasks like displaying, editing and updating the data with minimum effort. NET 2.0 has got some smart and intelligent new data source controls which can even manipulate specialized data sources like XML files.