On referring expressions in information systems derived from conceptual models

Abstract

We apply recent work on referring expression types to the issue of identification in conceptual modelling. In particular, we consider how such types yield a separation of concerns in a setting where an information system based on a conceptual schema is to be mapped to a relational schema plus SQL queries. We start from a simple object-centered representation (as in semantic data models), where naming is not an issue because everything is self-identified (possibly using surrogates). We then allow the analyst to attach to every class a preferred "referring expression type", and to specify uniqueness constraints in the form of generalized functional dependencies. We show (1) how a number of well-formedness conditions concerning an assignment of referring expressions can be efficiently diagnosed, and (2) how a concrete relational schema and SQL queries over this schema are derived from a combination of the conceptual schema and queries over it, once identification issues have been separately resolved as above.