Tabular and multidimensional models update#
Tabular and multidimensional models plus#

In this case there are two modes of execution too: ROLAP and DirectQuery. Regarding to passthrough mode, as its name implies, sends the query directly to data source engine, so both operations: data processing and business logic are performed there. XVelocity is a brand new system introduced with BISM for use in tabular models, consisting of a column based data storage engine, which combines sophisticated compression and search algorithms, to offer, without using indexes or aggregations, excellent performance in speed response to our queries. MOLAP is the intermediate storage system traditionally used in Analysis Services, and as the name suggests, is optimized for use in multidimensional models development (OLAP cubes). In turn, using this cache mode we must choose two different storage engines: MOLAP or xVelocity. The caching mechanism gets the data from the original source and stored it in a data structure based on a compression algorithm optimized for high-speed access. Watching the workflow of this architecture in a bottom-top direction, in first place, we find the data access layer, which is responsible for performing the information extraction resident in the data sources we connect, existing two modes for this extraction: cache and passthrough. This integration between work philosophies, and hence on the underlying technologies (multidimensional and relational), results in an architecture distributed in three layers, as we see in the following image, with response capacity to users with very different needs in all concerning tasks related to data analysis.

Tabular and multidimensional models update#

Similarly, when we update an UDM project to SQL Server 2012, it will be deemed as a BISM project for all purposes. Therefore, from now on, the term UDM is replaced for BISM, when we mention the development model used by Analysis Services.

Tabular and multidimensional models plus#

A single model for all analytical needsīISM becomes the new model for the development of BI solutions that fulfills the analysis requirements of all kind users.īISM represents an evolution from Unified Dimensional Model (UDM) towards a combined model that offers all UDM multidimensional development features plus new features based on a relational analysis engine, what enrich the current SQL Server offer in the analytical services area.

However, since the first public announcements about BISM so far, new details have been revealed about the architecture of this technology, allowing us to be more precise in the descriptions of it.īISM. In this article we’ll focus on development of analytical tabular models, an integral part of Business Intelligence Semantic Model (BISM), the new paradigm for developing Business Intelligence (BI) solutions based on SQL Server 2012 Analysis Services.Īs was already mentioned in the introductory article about PowerPivot, the incorporation of BISM into Analysis Services makes SQL Server one of the most powerful solutions within the current BI arena. The recent SQL Server 2012 release (formerly codenamed Denali) is accompanied, as usual in any new version, for several interesting improvements.