Qualifying Answers According to User Needs and Preferences

Article type: Research Article

Authors: Gaasterland, Terry | Lobo, Jorge

Affiliations: Mathematics and Computer Science, Argonne National Laboratory, gaasterland@mcs.anl.gov | Deft. of EECS, University of Illinois at Chicago, jorge@eecs.uic.edu

Abstract: This paper presents a rigorous methodology for using annotated logic programming techniques to handle user preferences and needs in answering database queries. Two alternative transformations turn a database program into a new program that returns answers to queries according to qualitative labels. The two transformations have different semantics and are each appropriate in different situations. We have modified the standard definitions of annotated logic programs to handle user needs and preferences in databases. In the formalism, the user provides a lattice of domain-independent values that define preferences and needs and a set of domain specific user constraints qualified with lattice values. After the original database and the user constraints have been transformed into a new annotated deductive database, query-answering procedures for deductive databases are used, with minor modifications, to obtain annotated answers to queries. Because preference declaration is separated from data representation and management, preferences can be easily altered without touching the database. The resulting query language allows users to ask for answers at different preference levels.

DOI: 10.3233/FI-1997-32202

Journal: Fundamenta Informaticae, vol. 32, no. 2, pp. 121-137, 1997