Visual query operators for temporal databases

Many recent proposals in the literature present easy-to-use query languages, based on visual representations of the database and direct manipulation mechanisms. Such proposals essentially deal with conventional query operations, whereas little effort is devoted to investigate friendly environments for querying temporal databases. Nevertheless, temporal aspects are generally considered extremely relevant in several database applications. Thus, the various users should be provided with powerful and simple query systems also exhibiting temporal features. While attempting to meet this need, we propose a visual query system for temporal databases. It adopts a diagrammatic representation of the database schema (including temporal classes and relationships), on which conventional as well as temporal visual query operators can be applied. In this paper we concentrate on the temporal operators, showing both examples of usage and formalization