Top_Keyword: An Aggregation Function for Textual Document OLAP

For more than a decade, researches on OLAP and multidimensional databases have generated methodologies, tools and resource management systems for the analysis of numeric data. With the growing availability of digital documents, there is a need for incorporating text-rich documents within multidimensional databases as well as an adapted framework for their analysis. This paper presents a new aggregation function that aggregates textual data in an OLAP environment. The TOP_KEYWORD function (TOP_KW for short) represents a set of documents by their most significant terms using a weighing function from information retrieval: tf.idf.