Conceptual level Logical level Physical level Data

This paper presents a proposal for a Data Warehouse Conceptual Data Model which allows for the description of both the relevant aggregated entities of the domain| together with their properties and their relationships with other relevant entities|and the relevant dimensions involved in building the aggregated entities. The proposed Data Warehouse Conceptual Data Model is able to capture the database schemata expressed in the most interesting traditional Semantic Data Models and Object-Oriented Data Models; it is able to introduce complex descriptions of the structure of aggregated entities and multiply hierarchically organised dimensions; it is based on Description Logics, a class of formalisms for which it is possible to study the expressivity in relation with decidability of reasoning problems and completeness of algorithms; it supports the most important reasoning services for the basic Data Warehouse operations.