Design And Implementation Of A Relational Olap System Based On Materialized Views

Relational OLAP (ROLAP), which is widely used especially when there are large-scale multidimensional data with large numbers of dimensions, provides efficient OLAP query by using MVs (Materialized View). Because of the existing of MVs and the limitation of computer resources, View Maintenance (VM) and View Selection Problem (VSP) are the two key problems in order to implement an ROLAP system. There are many existing VSP and VM algorithms that have their own shortcuts as well as strong points. We investigate ROLAP from the perspective of system implementation and focus on VSP in this paper. Firstly we review the history of OLAP and summarize what functionalities are necessary for a typical OLAP system. Then after studying those existing VSP algorithms and analyzing their characteristics, a simply and easy-implemented VSP algorithm that can run efficiently is introduced. In order to validate the new VSP algorithm, our team developed a prototypal ROLAP system whose name is SEU_OLAP. SEU_OLAP, which is composed of an OLAP Server, an OLAP Client and a Report Tool, can perform many functions, such as Drill-up, Drill-down, Slice and report processing. A common used VM algorithm is also quoted in SEU_OLAP for the purpose of increasing practicability. Finally we work out the test results of the VSP algorithm using the prototypal OLAP system, which proved that the algorithm is very suitable for small-scale business applications.