Selected papers of the 9th annual ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Dense-order constraint databases (extended abstract)
PODS '95 Proceedings of the fourteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Finitely representable databases
Journal of Computer and System Sciences - Special issue on principles of database systems
Relational expressive power of constraint query languages
Journal of the ACM (JACM)
Querying spatial databases via topological invariants
PODS '98 Proceedings of the seventeenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
PODS '98 Proceedings of the seventeenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
An expressive language for linear spatial database queries
PODS '98 Proceedings of the seventeenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
The DEDALE system for complex spatial queries
SIGMOD '98 Proceedings of the 1998 ACM SIGMOD international conference on Management of data
A constrant-based spatial extension to SQL
Proceedings of the 6th ACM international symposium on Advances in geographic information systems
First-Order Queries on Finite Structures Over the Reals
SIAM Journal on Computing
Foundations of Databases: The Logical Level
Foundations of Databases: The Logical Level
The power of languages for the manipulation of complex values
The VLDB Journal — The International Journal on Very Large Data Bases
Hauptvortrag: Quantifier elimination for real closed fields by cylindrical algebraic decomposition
Proceedings of the 2nd GI Conference on Automata Theory and Formal Languages
Manipulating Spatial Data in Constraint Databases
SSD '97 Proceedings of the 5th International Symposium on Advances in Spatial Databases
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Linear constraint databases and query languages are appropriate for spatial database applications. Not only the data model is natural to represent a large portion of spatial data such as in GIS systems, but also there exist efficient algorithms for the core operations in the query languages. However, an important limitation of the linear constraint data model is that it cannot model constructs such as "Euclidean distance." A previous attempt to expend linear constraint languages with the ability to express Euclidean distance, by Kuijpers, Kuper, Paredaens, and Vandeurzen is to adapt two fundamental Euclidean constructions with ruler and compass in a first order logic over points. The language, however, requires the input database to be encoded in an ad hoc LPC representation so that the logic operations can apply. This causes a problem that sometimes queries in their language may depend on the encoding and thus do not have any natural meaning. In this paper, we propose an alternative approach and develop an algebraic language in which the traditional operators and Euclidean constructions work directly on the data represented by "semi-circular" constraints. By avoiding the encoding step, our language do not suffer from this problem. We show that the language is closed under these operations.