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Unit 10: Multi-dimensional Data Models and Aggregation

is transformed into notes

10.4 roLap Model

Relational OLAP (or ROLAP) is the latest and fastest growing OLAP technology segment in the
market. Many vendors have entered the fray in this direction (e.g. Sagent Technology and Micro-
strategy). By supporting a dictionary layer of metadata, the RDBMS products have bypassed any
requirement for creating a static, multidimensional data structure as shown in Figure 10.12.

figure 10.12: roLap architecture

This approach enables multiple multidimensional views of two-dimensional relational tables to
be created, avoiding structuring data around the desired view. Some products in this segment
have supported strong SQL engines to support the complexity of multidimensional analysis. This
includes creating multiple SQL statements to handle user requests, being ‘RDBMS’ aware’ and
also being capable of generating the SQL statements based in the optimizer of the DBMS engine.
While flexibility is the attractive feature of ROLAP, there exist products which require the use of
denormalized database design. However, of late there is a noticeable change or realignment in
ROLAP technology. Firstly, there is a shift towards pure middle-ware technology so as to simplify
the development of multidimensional applications. Secondly, the sharp delineation between
ROLAP and other tools and RDBMS products are now eager to provide multidimensional
persistent structures with facilities to assist in the administrations of these structures. Notable
among vendors of such products are micro-strategy (DSS Agent/DSS server), Platinium/
Perodea Software (Beacon), Information Advantage (AxSys), Informix/Stanford Technology
Group (Metacube) and SyBASE (HighGate Project).

Task Discuss OLAP application identify its characteristics.

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