A paraconsistent relational data model

Abstract

Abstract We present a generalisation of the relational data model based on a 4-valued paraconsistent logic. Our data model is capable of manipulating incomplete as well as inconsistent information. For this model, we define algebraic operators that are generalisations of the usual operators, such as union, selection, join, on ordinary relations. Our data model can underlie any database management system that deals with incomplete or inconsistent information. As another application of our model and its algebra, we present a bottom-up method for constructing the weak well-founded model of general deductive databases. This method can be very simply extended to construct the well-founded model. Keywords: Paraconsistent relationsRelational algebraGeneral deductive databasesWeak well-founded model