Conceptual Graphs for Relational Databases

In order to apply conceptual graphs to Databases according to the indications of Sowa, we introduce λ-expressions and sets associated with CGs and introduce built-in relations to express general conditions for joining relations. The definition and test of well-formed query graphs is discussed as well as the evaluation of such a query. Views, deductive Databases and nested queries are shown to fit within this framework. Finally, we outline the ability of a CG base to cope with some Database problems where the relational model is too rigid with its separation of data from queries.