Abstract
In 2013, Chris Date published a book about the view update problem in the context of the Relational Model. He presented several detailed examples of different varieties of view updates and characterised their behaviour, in the process deriving a set of principles for updating views based on the notion of information equivalence of view schemas. In this paper we discuss work in progress that examines how Date’s operational definition of information equivalence can be formally characterised using Hull’s concept of relative information capacity. As a proof of concept, we use an extension of Miller’s schema intension graph formalism to model the information equivalence of Date’s restriction view example.