ActivePivot implements the standards of OLAP:
- The MDX query language
- The XMLA protocol for communications
So does Tableau Software.
When a multidimensional (MDX) query is sent to an OLAP provider like ActivePivot, a cell set is returned, encoded in the XMLA protocol. Most OLAP frontends (Microsoft Excel in particular) rely on a "multidimensional format" to represent the cell set in XMLA. But a few rely on the older "tabular format", that is the case of Tableau Software (and also Microsoft SQL Server Reporting Services).
ActivePivot supports the XMLA multidimensional format since version 2.0 and the tabular format since version 4.3.3. ActivePivot 4.3.3 has been tested and works with Tableau Software.