This past week, SAP and Tableau announced that you can use Tableau to visualize your SAP BW data. This is great news and speaks to the openness of SAP BW. Some people were curious how this works. It is simple actually. SAP BW has supported the MDX query language since it was launched in the late 1990's. There are three ways to send an MDX query to SAP BW:
1. OLE DB for OLAP (ODBO)
2. XML for Analysis (XMLA)
3. OLAP BAPI
Whichever "transport" you use, you will hit the same MDX query processor on BW. The MDX query language is the same standard used by SAP BW, Microsoft Analysis Services, Teradata OLAP, Oracle Database OLAP Option, Kognitio Pablo, etc.
So, it was easy to connect Tableau to SAP BW because Tableau issues MDX queries and SAP BW supports MDX queries. Also note that Tableau will work with SAP BW on HANA and SAP BW that runs without HANA. You can read more and see a demo here: Demo of Tableau running on SAP BW.
Of course, the next question is, Tableau now works on Microsoft Analysis Services and SAP BW. When will Tableau officially support Teradata OLAP, Oracle Database OLAP Option, Kognitio Pablo, etc?