The expressive power of stratified logic programs
Information and Computation
Selected papers of the 9th annual ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Constraint query languages (preliminary report)
PODS '90 Proceedings of the ninth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Linear approximation of planar spatial databases using transitive-closure logic
PODS '00 Proceedings of the nineteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Query Languages for Constraint Databases: First-Order Logic, Fixed-Points, and Convex Hulls
ICDT '01 Proceedings of the 8th International Conference on Database Theory
Constraint Databases
Deciding Termination of Query Evaluation in Transitive-Closure Logics for Constraint Databases
ICDT '03 Proceedings of the 9th International Conference on Database Theory
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In this paper we compare the expressive power of s fixed-point logics on linear or dense order constraint databases. This comparison is not done on absolute terms, i.e. by comparing their expressive power for arbitrary queries, rather for definability of partially recursive queries. The motivation for choosing this benchmark comes from fixed-point logics as query languages for constraint databases. Here, non-recursive queries are of no practical interest. It is shown that for linear constraint databases already transitive closure logic is expressive enough to define all partially recursive queries, i.e., transitive-closure logic is expressively complete for this class of databases. It follows that transitive-closure, least, and stratified fixed-point logic are equivalent with respect to this benchmark.