Performing live time-traversal queries on RDF datasets

This article introduces a methodology to perform live time-traversal queries on RDF datasets and software based on this procedure. It offers a solution to manage the provenance and change-tracking of entities described using RDF. Although these two aspects are crucial factors in ensuring verifiability and trust, some of the most prominent knowledge bases - including DBpedia, Wikidata, Yago, and the Dynamic Linked Data Observatory - do not support time-agnostic SPARQL queries, i.e. queries across the various statuses an entity may have assumed in time. The OpenCitations Data Model (OCDM) describes one possible way to track provenance and entities' changes in RDF datasets, and it allows restoring an entity to a specific status in time (i.e. a snapshot) by applying SPARQL update queries. The methodology and library presented in this article are based on the rationale introduced in the OCDM. We also develop benchmarks proving that such a procedure is efficient for specific queries and less efficient for others. To date, as far as we know, our library is the only software supporting all the time-related retrieval functionalities without pre-indexing data.