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We extend Chandra and Harel's seminal work on computable queries for re-lational databases to a setting in which also spatial data may bepresent, using a constraint-based data model. Concretely, we introduce bothcoordinate-based and point-based query languages that are complete in the sense that they can express precisely all computable queries that are(More)
We investigate properties of finite relational structures over the reals expressed by first-order sentences whose predicates are the relations of the structure plus arbitrary polynomial inequalities, and whose quantifiers can range over the whole set of reals. In constraint programming terminology, this corresponds to Boolean real polynomial constraint(More)
In this paper, we discuss augmentations of the nested relational algebra with programming constructs, such as while-loops and for-loops. We show that the algebras obtained in this way are equivalent to a slight extension of the powerset algebra, thus emphasizing both the strength and the naturalness of the powerset algebra as a tool to manipulate nested(More)
Proefschrift voorgelegd tot het behalen van de graad van doctor in de Wetenschappen aan de Universiteit Antwerpen te verdedigen door Toon CALDERS Acknowledgements I would like to thank the many people that contributed to the realization of this thesis. First of all, I would like to thank my advisor, Jan Paredaens, for his guidance during my doctoral(More)