Expressing OLAP Preferences

Multidimensional databases play a relevant role in statistical and scientific applications, as well as in business intelligence systems. Their users express complex OLAP queries, often returning huge volumes of facts, sometimes providing little or no information. Thus, expressing preferences could be highly valuable in this domain. The OLAP domain is representative of an unexplored class of preference queries, characterized by three peculiarities: preferences can be expressed on both numerical and categorical domains; they can also be expressed on the aggregation level of facts; the space on which preferences are expressed includes both elemental and aggregated facts. In this paper we propose a preference algebra for OLAP, that takes into account the three peculiarities above.