Description Logics for Information Modeling and Access
presented by Enrico Franconi, Open University of Bolzano
what is an Ontology? It is a formal conceptualization of the world: a conceptual schema, a set of constraints.
an ontology language introduces concepts (classes/entities), properties of concepts (slots/attributes/roles), relationships (associations) and additional constraints. [it may be simple, frame-based, logic-based]
UML is a kind of ontology
The database technology widely available today relies on the assumption of the completeness of the dataset. This structure is designed in a logical schema (tables, relations) that enables for queries at a logical level. An ontology expands of one level this framework, enabling for conceptual schema, which give the user the ability to use constraints for deductions. The ontology has a richer vocabulary than the database and enables for conceptual query on the dataset.
[see also DLR description logic]