SHACL Validation under Graph Updates (Extended Paper)

TL;DR

This paper investigates static validation of RDF graphs under updates using SHACL, introducing a new update language, embedding techniques, and analyzing complexity, with a prototype implementation demonstrating practical feasibility.

Contribution

It introduces a SHACL-based update language and a regression technique to reduce validation under updates to constraint satisfiability, advancing reasoning about evolving RDF graphs.

Findings

Validation under updates can be reduced to SHACL constraint satisfiability.

Complexity analysis of validation problem for key SHACL fragments.

Prototype implementation demonstrates practical static validation capabilities.

Abstract

SHACL (SHApe Constraint Language) is a W3C standardized constraint language for RDF graphs. In this paper, we study SHACL validation in RDF graphs under updates. We present a SHACL-based update language that can capture intuitive and realistic modifications on RDF graphs and study the problem of static validation under such updates. This problem asks to verify whether every graph that validates a SHACL specification will still do so after applying a given update sequence. More importantly, it provides a basis for further services for reasoning about evolving RDF graphs. Using a regression technique that embeds the update actions into SHACL constraints, we show that static validation under updates can be reduced to (un)satisfiability of constraints in (a minor extension of) SHACL. We analyze the computational complexity of the static validation problem for SHACL and some key fragments. Finally, we present a prototype implementation that performs static validation and other static analysis tasks on SHACL constraints and demonstrate its behavior through preliminary experiments.