Gone but not forgotten:  Transfer Rules

Transfer rules are available only for classic DataSources in SAP BW; for new DataSources, transformations are used instead.

SAP BW offers several ways to define a transformation:

    *  Simple field assignments, where a field of the transfer structure is assigned to a field of the InfoSource

    *  Constant value assignment, where a constant value is assigned to a field of the InfoSource

    *  Formulas, where predefined transformation functions can be used to fill a field of the InfoSource

    *  Routines, which allow you to implement custom ABAP code for complex transformations