Is BW’s ETL too simple for its own good?
I think over the past few years SAP BW would be the module that saw an exponential increase in the number of developers. I think it is because of the simplicity of BW’s ETL and modeling components more than anything else i.e if your only objective is to bring the data from a transaction system into your BW system. But this simplicity comes with its own set of demons. A few I can think of are:
- BW doesn’t require its developer to be knowledgeable about schema’s or models, heck you don’t need to even understand Data warehousing to extract data and run a report.
- Everybody knows that BW uses full and delta, but how many developers actually take time in really understanding the various delta’s and the consequences of using them.
- Taking into account the scalability of a model in case of huge buildup in data at a later stage.
Most of the developers approach the BW from a report perspective, where in the format and the report structure govern how you build a model, but they fail to see that the success or failure of a BW implementation is decided in this initial design phase itself. I have come across so many “BW experts” who don’t even know what a star or an extended star really mean. Anybody can pick up the way to bring in data into BW but I think its in the best interests of a project to ask basic questions like why did I chose a particular dimension for an infoobject or why would I go for a particular infoprovider for a particular requirement and save a lot of flak both for yourself and BW in general at a later stage.
My blog I hope would make someone new wanting to learn BW to really understand data warehousing concepts first and then learn the fundamentals of BW and how it provides for a better warehousing before implementing a model on a BW project.