Most activities within SAP Business Warehouse require you to regularly confirm the difference between what you know versus what is really going on in the BW system itself.
In the beginning, this is a steep learning curve as you spend more time absorbing the current BW system configuration rather than confirming it against what you know. This is especially true for new BW Developers and BW Support personnel. The more time you spend with the same system the easier it gets. When you start working with a different BW system you spend more time absorbing it.
This cycle between absorbing and confirming does get easier; as the years go by you spend more and more time just confirming what you know to be true, in the current BW system.
The process of confirming what you know is done directly within the BW system itself.
The effort involved in absorbing a specific BW system can be greatly reduced if all BW system personnel have kept up the effort to document the high and middle level features of the system.
Documenting low level features like the ABAP routines or the query selection restrictions is not worth the time and money. If you need to know this level of detail then roll up your sleeves and get into the BW system itself.
The real benefit of custom BW data flow diagrams is realised when you are still absorbing a portion of the BW DataModel and need to get down into the low level detail. The diagram can efficiently transition you from:
- The high level: I need more about Order Goods Receipts;
- The middle level: Ok, the diagram indicates ECC and SRM data flows;
- The low level: Now I’ll jump into those transformations for the field mappings.
The above sequence of activities can take hours to get the confidence you’re looking at the right spot in the BW system.
“you start too deep, too quick; then you
can not see the forest because of all the trees”
Custom data flow diagrams make absorbing a BW system an efficient process. It can take as little as a few minutes to locate the right components of the DataModel where you truly need to spend time deep diving into the low level detail. Consider: Where in the BW Administrator Workbench can you quickly identify active but decommissioned objects that should not be used? [Good luck with that]
The efficiency of custom BW bata flow diagrams is achieved because of ‘what is’ and ‘what is not’ in the diagram. There is an ability to quickly generate standard BW data flow diagrams that can list related components and even lay them out visually. The usefulness of these dynamic images is limited to only ‘what is involved’ and does not offer a clean way to add comment boxes with insightful instructions. There is also no way to relate two components unless the data flows between them.
When you create/view the same standard BW data flow diagram tomorrow there is a good chance it has been re-arranged (slightly). It will be close to what you studied yesterday but will not be an exact layout match. Fundamentally you will have to spend additional brain power re-assuring yourself that you are indeed looking at is the same diagram. Over time, this gets frustrating and you minimise the time spent using the standard BW data flow diagrams.
Do you maintain a personal notebook of small data flow sketches with insights and instructions scribbled all around it? There is a good chance the rest of the BW Team would benefit from your time and effort to create a custom BW data flow diagram.
In my opinion; what makes a data flow diagram go from ok to excellent?