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

This paper presents some highlights about the concept of multidimensional database and On-Line Analytical Processing (OLAP), a technology used in the context of decision support. It mainly focuses on multidimensional data models and manipulations. We propose both an inventory and a classification of the elementary operations underlying OLAP treatments. We describe several typical complex manipulations based on these elementary operations. Throughout the paper, we present the informal concepts stemming from users' needs and the formal proposals of research works. Hence it provides an entry point in the domain of OLAP modeling and querying.