Questions and Answers 

The following questions arose while the package concept was being developed:

General

·        Who are the main users of the package concept?

The concept is used primarily by developers and teams within SAP. The teams (such as the Package Architecture Team and the Decoupling Team) carry out global modularization, while individual developers or groups of developers are responsible for structuring local functions (of a transaction or application area, for example).

·        How are "local names" related to the package concept?

Local namespaces (identical names in different packages) have nothing to do with the package concept These are two separate topics.

·        How is the package concept related to the application component hierarchy?

The application component hierarchy is a method of splitting up the SAP System from a logical or business point of view. Packages are a method of modularizing the system from a technical point of view. This technical modularization can, but need not, match the logical division of the system. Assignments should be made however between these two views.

·        How are the packages related to UML packages?

It is impossible to give a detailed yet brief answer to this question. SAP packages correspond roughly to UML packages. (The SAP use access concept is roughly equivalent to the UML “dependency relationship”). The only difference is that SAP packages do not have namespaces.

·        Can function modules of a function group be contained in different packages?

No. This is not technically possible. It is also not semantically desirable, since each function group should group a set of functions that belong together logically. This indivisibility principle also applies, for example, to programs and screens. Screens must be assigned to the package containing the program with which they are associated.

Modularization

·        Do all developers have to decouple their applications simultaneously?

No. Given the differences in goals, priorities, and resources, this would not be feasible. It is simpler to decouple parts of the SAP system step-by-step. To ensure that users do not face problems when a developer revokes visibility for an element, you can set various parameters and attributes to prevent programs terminating.

·        How can software be structured on several levels using packages?

There are two ways to do this. One option is nesting, since elements of embedded packages can never use elements of their surrounding packages. The other is a chain of one-way use accesses. In contrast to use accesses, nesting allows you to "hide" many elements.