Towards On-Line Analytical Processing for Database Summaries: The Core Algebra

In this paper, we propose a general framework to explore and analyze database summaries built from massive data sets. Summaries are multidimensional vague concepts, represented by a set of fuzzy terms provided on each attribute of a database relation as domain knowledge. We define a logical multidimensional data model called summary partition, as data cubes do in OLAP systems, in order to provide the end-user with a reduced and well-suited presentation of the data. The overall on-line summarization process is then intended to support a new approach to OLAP. To achieve this we introduce a collection of algebraic operators over the space of summary partitions : relational, granularity and restructuring operators are defined as the core algebra for online analytical processing of summarized versions of the data.