Towards a theory of spatial database queries (extended abstract)

Abstract

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. The main purpose of the paper is to open up new grounds for theoretical research in the area of spatial database systems. Consequently, many open problems are indicated.