Comparing DirectQuery and ROLAP for real-time access

In the multidimensional model in SSAS, there is a storage mode called relational OLAP (ROLAP), which is the multidimensional solution for allowing real-time access to relational data sources. In the tabular model in SSAS, the solution for real-time access is a query mode called DirectQuery, which uses a fundamentally different architecture and provides a different set of capabilities. This blog post will explain the differences between the two.