Abstract
We show that it is natural to extend the concept of database updates to encompass databases with incomplete information in the form of null values, or tuple attribute values that are known to exist but whose exact value is not known. Our approach embeds the incomplete database and the updates in the language of mathematical logic, which we believe has strong advantages over relational tables and traditional data manipulation languages in the incomplete information situation. We present semantics for our update operators, and provide an algorithm to perform the operations. The computational complexity of the algorithm is examined, and a lazy evaluation scheme coupled with simple user-supplied cost limits is recommended to avoid undesirable expense during execution. This paper extends results presented in [Winslett 86a].
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7. References
S. Abiteboul, G. Grahne, “Update Semantics for Incomplete Databases,” Proc. VLDB Conf., Stockholm, August 1985.
R. Fagin, J. D. Ullman, and M. Y. Vardi, “On the Semantics of Updates in Databases,” Proc. of the 2nd ACM PODS, April 1983.
R. Fagin, G. M. Kuper, J. D. Ullman, and M. Y. Vardi, “Updating Logical Databases,” Proc. of the 3rd ACM PODS, April 1984; reprinted in Advances in Computing Research 3, JAI Press, 1986.
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M. Winslett, “A Model-Theoretic Approach to Updating Logical Databases,” Stanford Univ. Computer Science Dept. Tech. Report, January 1986. A preliminary version appeared as “A Model-Theoretic Approach to Updating Logical Databases (Extended Abstract),” Proc. of the 5th ACM PODS, Cambridge, March 1986.
M. Winslett, “Is Belief Revision Harder Than You Thought?”, Stanford Computer Science Dept. Tech. Report, June 1986. A shortened version will appear in Proc. AAAI Conference, Philadelphia, August 1986.
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Winslett, M. (1986). Updating logical databases containing null values. In: Ausiello, G., Atzeni, P. (eds) ICDT '86. ICDT 1986. Lecture Notes in Computer Science, vol 243. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-17187-8_51
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DOI: https://doi.org/10.1007/3-540-17187-8_51
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