Open AccessRecursion in SPARQL
Author(s) -
Juan L. Reutter,
Adrián Soto,
Domagoj Vrgoč
Publication year - 2021
Publication title -
semantic web
Language(s) - English
Resource type - Journals
eISSN - 2210-4968
pISSN - 1570-0844
DOI - 10.3233/sw-200401
Subject(s) - sparql , computer science , semantics (computer science) , syntax , recursion (computer science) , semantic web , property (philosophy) , extension (predicate logic) , rdf , operator (biology) , information retrieval , theoretical computer science , plug in , linked data , named graph , programming language , artificial intelligence , philosophy , biochemistry , chemistry , epistemology , repressor , transcription factor , gene
The need for recursive queries in the Semantic Web setting is becoming more and more apparent with the emergence of datasets where different pieces of information are connected by complicated patterns. This was acknowledged by the W3C committee by the inclusion of property paths in the SPARQL standard. However, as more data becomes available, it is becoming clear that property paths alone are not enough to capture all recursive queries that the users are interested in, and the literature has already proposed several extensions to allow searching for more complex patterns. We propose a rather different, but simpler approach: add a general purpose recursion operator directly to SPARQL. In this paper we provide a formal syntax and semantics for this proposal, study its theoretical properties, and develop algorithms for evaluating it in practical scenarios. We also show how to implement this extension as a plug-in on top of existing systems, and test its performance on several synthetic and real world datasets, ranging from small graphs, up to the entire Wikidata database.