Browsing by Author "Bertossi Duran, Leopoldo"
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- ItemQuery evaluation in almost consistent databases using residues(IEEE, 1998) Arenas Saavedra, Marcelo Alejandro; Bertossi Duran, Leopoldo; Chomicki, JanThe authors consider the problem of logical characterization of the notion of correct answers in a relational database that may violate given integrity constraints. This notion is captured in terms of the possible repaired versions of the database. A computational counterpart of the semantic notion is provided in terms of the reconstruction of the database as a deductive database to which concepts and techniques from semantic query optimization are applied with the purpose of computing correct answers.
- ItemSpecifying active databases in the situation calculus(IEEE, 1998) Bertossi Duran, Leopoldo; Pinto Bustamante, Javier Andres; Valdivia Pinto, Ricardo ElíasThe paper provides a predicate logic based semantics for active rules in active databases. Previous work has been done to provide the semantics of execution of active rules. In part, this work has been directed towards providing a unifying criteria regarding the meaning of active rules, and to provide a framework for comparing different proposals for active database systems. The main contribution of the article is a proposal to integrate the specification of active rules with the specification of the dynamics of change (based on transactions) in relational databases. The approach extends previous work in which the situation calculus, a language of many sorted predicate logic, is used to specify updates in databases. To achieve this, the authors specify first the notion of database transaction in a situation calculus extended with the notion of occurrence, as proposed by Pinto. They concentrate mostly on the execution semantics of Starburst.