A general model for spatial databases is considered, which extends the relational model by allowing as tuple components not only atomic values but also geometrical figures. The model, which is inspired by the work of Kanellakis, Kuper and Revesz on constraint query languages, includes a calculus and an algebra which are equivalent. Given this framework, the concept of spatial database query is investigated. Thereto, Chandra and Harel's well-known consistency criterion for classical relational queries is adapted. Various adaptations are proposed, depending on the kinds of geometry in which the spatial information in the database is to be interpreted. The consistency problem for calculus queries is studied. Expressiveness issues are examined.

A simple, graph-oriented database model, supporting object-identity, is presented. For this model, a transformation language based on elementary graph operations is defined. This transformation language is suitable for both querying and updates. It is shown that the transformation language supports both set-operations (except for the powerset operator) and recursive functions.

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We extend Chandra and Harel's seminal work on computable queries for relational databases to a setting in which also spatial data may be present, using a constraint-based data model. Concretely, we introduce both coordinate-based and point-based query languages that are complete in the sense that they can express precisely all computable queries that are generic with respect to certain classes of transformations of space, corresponding to certain geometric interpretations of spatial data. The languages we introduce are obtained by augmenting basic languages with a``while'' construct. We also show that the respective basic point-based languages are complete, relative to the subclass of the corresponding generic queries consisting of those that are expressible in the relational calculus with real polynomial constraints. Academic Press