by senthil
5. October 2009 12:38
Relational databases like Oracle or Microsoft SQL Server can scale upto terabytes but Multi-dimensional databases are not huge compared to Relational. Most of the companies hold their Enterprise Datawarehouse Platform on Relational environment.
That means you have to use SQL or tools like Cognos Report studio to roll up and produce BI Reports.
Advantage with Essbase connecting to Relational tables can provide analysts the benefits of multi-dimensional functionality and auto aggregation.
Essbase Hybrid Analysis
Hybrid analysis allows Essbase to store the lower level data, for example Contract level data in Relational DB, but the aggregated data by Country, or Region in Essbase. Integration Services tool is used to link the Essbase to Relational data source.
The data in the RDBMS is mapped to Essbase outline that is defined by Hybrid analysis. Reporting tools like Microsoft Excel can retrieve the data from both the databases (Essbase and Relational) through hybrid analysis. Hybrid analysis can apply to both BSO and ASO storage models.
Some important guidelines
- Hybrid Analysis is not supported on accounts dimensions.
- Only the lowest level members of a dimension can be enabled for Hybrid Analysis.
- Essbase ignores all member properties, such as formulas, UDAs, and aliases for members that are enabled for Hybrid Analysis.
Advance Relational Access
Integration Services uses Advanced Relational Access to give Essbase end users direct access to data from relational databases or data warehouses. Queries to access the Relational data are written in MDX. Only ASO outlines are supported in Advanced Relational Access outlines. Block storage is not supported.
When Advanced Relational Access is enabled, all Accounts dimension members are stored in Essbase. Non accounts dimensions, only the root members are stored in Essbase. All other members are accessed directly from Relational Db.
XOLAP (extended online analytic processing)
New feature in System 11.x is a Essbase multidimensional database that stores only the outline metadata and retrieves data from a relational database at query time. XOLAP cube is developed and deployed using Essbase Studio. At that time there is no data loaded into it.
When XOLAP cube is accessed using Excel, it automatically generates SQL queries to retrieve the data from relational source. XOLAP cube is applicable for only ASO storage.
More MOLAP, ROLAP, And HOLAP concepts
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