On the expressive power of semijoin queries
Dirk Leinders (Limburgs Universitair Centrum, Belgium), Jerzy, Tyszkiewicz (Warsaw University), Jan Van den Bussche (Limburgs Universitair, Centrum, Belgium)
TL;DR
This paper investigates the expressive capabilities of the semijoin algebra in relational databases by introducing an Ehrenfeucht-Fraisse game to characterize its query power and limitations.
Contribution
It introduces a novel Ehrenfeucht-Fraisse game to analyze the expressive power of the semijoin algebra, providing a method to determine non-expressibility of certain queries.
Findings
The game characterizes the distinguishing power of the semijoin algebra.
It provides a technique to prove that some queries cannot be expressed in the semijoin algebra.
The approach clarifies the limitations of semijoin algebra in query expressiveness.
Abstract
The semijoin algebra is the variant of the relational algebra obtained by replacing the join operator by the semijoin operator. We provide an Ehrenfeucht-Fraiss\'{e} game, characterizing the discerning power of the semijoin algebra. This game gives a method for showing that queries are not expressible in the semijoin algebra.
Peer Reviews
No public reviews on file for this paper yet. If you reviewed it on a platform where reviews are public (OpenReview, ICLR, NeurIPS, ICML), you can paste yours below so the community can read it here.
Videos
No videos yet. Explain this paper in a talk, walkthrough, or lecture? Add one.
Taxonomy
TopicsConstraint Satisfaction and Optimization · Advanced Database Systems and Queries · Formal Methods in Verification