I have been working on several different functional specifications in the course of the project I have been involved with. I even made my own templates to try to optimize how people are doing functional specifications for SAP PI, which is different from ABAP.
One of the questions I am often asked in that regard is how mappings are defined. I have found that it is easier to explain the business to fill in a table in word. Much of what is going on are business definitions and rules, so it makes a lot of sense that it is the business that defines the rules.
Sometimes, when nobody was able to give any mapping, I was able to guess. Based on my knowledge on the subject and what looked like compared fields. This often resulted in some extra work with the testing by the business to make sure that everything is working as expected. It was the best we could do with the data that we had.
I have seen this both with Application-to-Application (A2A) integration as well as with Business-to-Business (B2B) integration. Mostly, it is because the consultants in one system do not know how that can translate to the other system.
For A2A integration there is something about catching both the consultant, who knows something about the different system, and bringing them into the same room and make them agree on the mapping. This is often the way that makes it easiest to solve the issues and make sure that all values work. Before this meeting, I found that it is a good idea to have some of the mapping done. This helps you to make sure you know what the challenge is. It also allows you to ask more intelligent and often irritating questions.
For B2B it is communication with one or more standards like EDIFACT. Here the SAP ERP functional consultant or better an EDI consultant is the person to ask. They do not always know the formats they want to integrate with. In some case they can give a good mapping specification, which will make it much easier to implement the mapping. It they have not been working with the document then it will take some time to get everything in order.
Everything is much easier if you have the right tool or template to support the process. I have, until now, not seen any good tools that made it easy for the business to perform the mapping. The tools that I have seen are the following.
There is a tool, like EDIFIX / GEFEG, which makes it a bit easier to see the mapping of EDIFACT and X12 documents. It is a tool that is targeted to the Edi consultant and shows how the mappings should be performed. If I remember correctly, this is a very expensive product to use.
There is, of course, my SAP PI mapping documentation. This converts a message mapping into an Excel document. This tool only works after mapping has been performed.
You can use Excel documents or Word tables (as I do in my functional templates). This is the normal old school way to make mappings. It is easy to use but it is not structured enough to help the business come to a good solution. The structure is a table with three columns, Source, mapping rules and Target.
Do you have any better solutions that will enable the business to easily make mappings and still capture as much information as necessary to perform the mapping afterwards in PI? I would love to hear your trick on how to get the business involved.