Incremental maintenance of horizontal view using PIVOT operation and differential files in relational DBMSs

To analyze multidimensional data conveniently and efficiently, OLAP(online analytical processing) systems are widely using views with horizontal form to represent measurement values over multiple dimensions, while conventional RDBMSs usually manage tables with vertical form. In this paper, we propose an incremental maintenance of these horizontal views which updates efficiently them according to the changes of base source tables. We first propose an overall framework processing queries over horizontal views transformed from source tables with vertical form. In order to execute this view maintenance process efficiently, we keep every changes of source tables into differential files then we modify the horizontal views with the differential files. Because differential files have vertical forms, their tuples are converted to horizontal forms which are identical to horizontal views then they are applied to the maintenance of these views. Experimental results show that the proposed method is more effective than existing methods.