Abstract
Hypothetical queries are queries embedding hypotheses about the database. The embedded hypothesis in a hypothetical query indicates, so to say, a state of the database intended for the rest of the query. Thus the answer to a hypothetical query h > q, with a hypothesis h, is in principle the result of evaluating q against the database revised with h. In case h is inconsistent with the database, query evaluation becomes a special case of counterfactual reasoning. However, the possible worlds semantics usually applied for this notion is not relevant for database applications due to reasons of inefficiency. In this paper we discuss and compare different approaches to hypothetical queries, paying special attention to potentials for efficient evaluation. As a central part of the paper we present and discuss our own approach “counterfactual exceptions”, which have the important property of, as opposed to the other approaches discussed, requiring only minor overhead in query evaluation. This approach is thus realistic for practical implementation and use in environments supporting large databases. The “price” for efficient evaluation is an altered semantics, as compared to the other approaches. However, it can be argued that this semantics is at least as appropriate for database applications as that of the other approaches mentioned.
Preview
Unable to display preview. Download preview PDF.
References
Andreasen, T., Christiansen, H. Counterfactual exceptions in deductive database queries. Proc. ECAI'96, 12th European Conference on Artificial Intelligence pp. 340–344, 1996.
Andreasen, T., Christiansen, H., and Larsen, H.L., eds. Flexible Query-Answering Systems, Kluwer, to appear 1997.
Bonner, A.J. Intuitionistic Deductive Databases and the Polynomial Time Hierarchy. Journal of Logic Programming (JLP), 33(1):1–47,1997.
Bonner, A.J. Hypothetical Datalog: Complexity and Expressibility. Theoretical Computer Science (TCS), 76:3–51, 1990.
Christiansen, H., A complete resolution method for logical meta-programming languages. Lecture Notes in Computer Science 649, pp. 205–219, 1992.
Clark, K.L., Negation as failure. Logic and Data Bases, Gallaire, H., and Minker, J. (eds.), Plenum Press, pp. 293–322, 1978.
Enderton, H.B., A Mathematical Introduction to Logic. Academic Press, 1972.
Gabbay, D.M., Giordano, L., Martelli, A., and Olivetti, N.,. Hypothetical updates, priority and inconsistency in a logic programming language. Lecture Notes in Computer Science (LN in Artificial Intelligence) 928, Springer-Verlag, pp. 203–216, 1995.
Gabbay, D.M. and Reyle, U., N-Prolog: An extension of Prolog with hypothetical implications. Journal of Logic Programming 2, pp. 319–355, 1984.
Gärdenfors, P., Knowledge in the Flux: Modeling the Dynamics of Epistemic States, MIT Press, 1988.
Giordano, L. and Martelli, A., A modal reconstruction of blocks and modules in logic programming. International Logic Programming Symposium, 1991.
Giordano, L., Martelli, A., and Rossi, G., Extending Horn clause logic with implication goals. Theoretical Computer Science, 1991.
Ginsberg, L.M., Counterfactuals. Artificial Intelligence 30, pp. 35–79, 1986.
Grahne, G., Mendelzon, A., Updates and subjunctive queries. Information and computation 116(2), pp. 241–252, 1995.
Kakas, A. C., Kowalski, R., Toni,F., The Role of Abduction in Logic Programming, In: Handbook of Logic in Artificial Intelligence and Logic Programming 5, pages 235–324, D.M. Gabbay, C.J. Hogger and J.A. Robinson eds., Oxford University Press, 1998).
Kowalski, R.A., Predicate logic as a programming language. Information Processing 74, pp. 569–574, 1974.
Kowalski, R.A., and Sadri, F., Logic programming with exceptions. Proc. of Eighth International Conference on Logic Programming, MIT Press, pp. 598–613, 1991.
Lewis, D, Counterfactuals. Harward University Press, 1973.
Lloyd, J.W., Foundations of logic programming, Second, extended edition. Springer-Verlag, 1987.
Miller, D., Lexical scoping as universal quantification, Proc. of Sixth International Conference on Logic Programming, MIT Press, pp. 268–283, 1989.
Monteiro, L. and Porto, A., Contextual Logic Programming, Proc. of Sixth International Conference on Logic Programming, MIT Press, pp. 284–302, 1989.
Nait Abdallah, M. A., Ions and local definitions in logic programming, Lecture Notes in Computer Science 210, pp. 60–72, Springer-Verlag, 1986.
Pereira, L.M., Aparício, J.N., and Alfares, J.J., Counterfactual reasoning based on revising assumptions. Logic Programming, Proceedings of the 1991 Internal Symposium, MIT Press 1991.
SICStus Prolog user's manual. Version 3 #6, SICS, Swedish Institute of Computer Science, 1997.
Winslett, M., Updating Logical Databases. Cambridge Tracts in Theoretical Computer Science, vol. 9, Cambridge University Press, 1990.
Author information
Authors and Affiliations
Editor information
Rights and permissions
Copyright information
© 1998 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Christiansen, H., Andreasen, T. (1998). A practical approach to hypothetical database queries. In: Freitag, B., Decker, H., Kifer, M., Voronkov, A. (eds) Transactions and Change in Logic Databases. DYNAMICS 1997. Lecture Notes in Computer Science, vol 1472. Springer, Berlin, Heidelberg. https://doi.org/10.1007/BFb0055505
Download citation
DOI: https://doi.org/10.1007/BFb0055505
Published:
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-65305-9
Online ISBN: 978-3-540-49449-2
eBook Packages: Springer Book Archive