We have used SAP for over a decade at work. Recently we started to use SAP PI as our middleware platform. Like everyone else we started with a training course and came back into the company keen and motivated to use every aspect of PI.
What we found was that some aspects of PI are very good others less so. We found if we used the visual mapping tool it soon became a complex mess for anything other than the most simple of maps. Using Java was often no help and we were forced to make RFC calls back in the SAP system to resove mapping issues.
An example of complexity we encountered would be our first EDIFACT interface. We built an EDIFACT to IDoc interface using the Seeburger tool on one side and the SAP IDoc interface on the other. Alas the two documents structures are quite different and it took us over 2 weeks to map them and even then we were forced to make design comprimises and fudges.
We now have the experience of two EDIFACT interfaces, the first “conventionally” designed, the second designed to our new simple design. The simple design still used Seeburger as before but instead of complex visual mapping, it mapped the EDIFACT order XML doument to a simplified XML document of the same structure, which was passed via a proxy into an ABAP class. Within the ABAP class, the fields were then directly mapped into an IDoc in memory, which was then processed as a normal IDoc by standard SAP functions. Total development time was a few days. No comprimises were made and the logic is clear to any ABAP developer.
It was a “nobrainer” decision when we started to design our new warehouse interfaces, we could do complex mapping in PI and split our logic over PI and ABAP or do simple PI mapping and have all the logic in one place in ABAP: proxies and simple design wins every time.
We are now in the process of rolling out new interfaces this year. They do all the heavy lifting in the SAP system where we have full access to all the business data we need, and a rich programming language that the whole team can use and understand. We then push the data out to PI via a proxy where the simplist of possible maps push it on to the final destination.
We have all the strengths of SAP standard business processing and logic within SAP ERP, glued with our bespoke but clean and simple ABAP, to the monitoring and delivering abilities of SAP PI.
The result is a solution than any functional user can understand, any ABAPer can change and any PI administrator can monitor. We benefit from full data tracability within the IDoc system and PI and there are no hidden secrets lurking that can easily be missed on a later date.