Hierarchical multidimensional modelling in the concept-oriented data model

In the paper the concept-oriented data model (COM) is described from the point of view of its hierarchical and multidimensional properties. The model consists of two levels: syntactic and semantic. Concepts are combinations of superconcepts while items are combinations of superitems. It is described how this model can be interpreted as a hierarchical coordinate system. Two operations of projection and de-projection are used in the mechanism of access path. Grouping and aggregation with roll up and drill down are implemented via multidimensional de-projection. The described approach can be applied to very different problems for multidimensional modelling including database systems, online analytical processing, knowledge based systems, ontologies, complex categorizations, knowledge sharing and semantics web.