The Tabular Model is an in-memory database in Analysis Services, introduced with the release of SQL Server 2012. It uses state-of-the-art compression algorithms and a multi-threaded query processor delivers fast access to Tabular Model objects and data through client applications like Microsoft Excel and Power View.
Data can be imported from multiple sources and models can be created containing relationships, calculated columns, measures, KPI's, etc. These models can then be deployed to an Analysis Services instance where they can be accessed by client applications.
Tabular Model supports data access through 2 modes:
- Cached mode - data retrieved from multiple sources (database, flat file, …) is cached in-memory
- DirectQuery mode – allows client applications to directly query the (SQL Server relational) source.