gyssensQcharlie.luc.ac.be laksQcs.concordia.ca We present a multi-dimensional database model, which we believe can serve as a con-ceptual model for On-Line Analytical Pro-cessing (OLAP)-based applications. Apart from providing the functionalities necessary for OLAP-based applications, the main fea-ture of the model we propose is a clear sepa-ration between structural aspects and the con-tents. This separation of concerns allows us to define data manipulation languages in a rea-sonably simple, transparent way. In particu-lar, we show that the data cube operator can be expressed easily. Concretely, we define an algebra and a calculus and show them to be equivalent. We conclude by comparing our ap-proach to related work. The conceptual multi-dimensional database model developed here is orthogonal to its im-plementation, which is not a subject of the present paper. 1

A flurry of buzzwords awaits anyone investigating database technology for decision support: data warehouse, Multi-dimensional and dimensional database, on-line analytical processing, star schema, slicing, dicing, drill-down and roll-up. We introduce the area via an example based on a long-ago project to design a repository on energy information for the US Department of Energy. Once we have introduced some terminology, we explore research issues associated with decision support databases, including representation, modeling, metadata, architectures and query processing. The purpose of this paper is to provide researchers with the background they need to contribute to this area. 1 Introduction Decision-support databases raise issues that are often quite distinct from those encountered in transaction processing systems. In this paper we present what we regard as important areas for research and development for decision-support databases, particularly those aspects that arise from the dime...