SAP ABAP Comparison of Enhancement Techniques

Due to the necessity of adjusting R/3 to meet the specific needs of a variety of customers, several different enhancement techniques were developed in the past. A short description of each of the various enhancement techniques follows.

Business Transaction Events (Open FI)

The Open FI enhancement technique was developed in the Financial Accounting component.

Open FI is based upon the following principles:

Application developers must define their interface in a function module, an assignment table is read in the accompanying (generated) code, and the customer modules assigned are called dynamically.

This technique differentiates between enhancements that are only allowed to have one
implementation and enhancements that can call multiple implementations in any sequence
desired. Both industry-specific and country-specific enhancements may be defined.

The concepts behind the Business Add-Ins enhancement technique and Open FI are basically the same. However, the two enhancement techniques do differ from each other in the following points:

Open FI can only be used to make program enhancements, that is, you can only enhance source code using Open FI. You cannot enhance user interface elements with Open FI like you can with Business Add-Ins.

Open FI assumes that enhancement will only take place on three levels (SAP - partners - customers), whereas with Business Add-Ins you can create and implement enhancements in as many software layers as you like.

Open FI uses function modules for program enhancements. With Business Add-Ins, ABAP Objects is used to enhance programs.

Enhancements in Transactions SMOD/CMOD

Making enhancements using the transactions SMOD/CMOD has the following disadvantages:

1. This enhancement technique assumes a two-tiered system infrastructure (SAP –customers).
2.The naming conventions in effect do not tolerate name extension.

Conclusion:

None of the techniques mentioned above can easily be extended to fulfill the requirements of a system infrastructure containing country versions, industry solutions, partners, and customers.
Business Add-Ins should be considered generalized Business Transaction Events that can be used to bundle program, menu and screen enhancements into a single add-in. Business Add-Ins
can be created and employed in each of the various software levels.