Blog Posts by Jeen Broekstra

  • [Citation needed]: provenance with RDF-star (RDF / SPARQL) 2021-04-26

    In any Knowledge Graph-based project, keeping track of where data comes from is important. When you know the source of your facts or assertions, you can contextualize those facts: how relevant is assertion X to my current research, is it from a source that I personally trust, and if I have two conflicting views how can I decide which source to go with? Apart from issues of trust and confidence, tracking the source also can serve more mundane goals, such as knowledge graph maintenance: source X has...

  • The default graph demystified (RDF / SPARQL) 2020-10-08

    The SPARQL default graph is a concept that can confuse even frequent SPARQL users. In this article, we will go over what the default graph actually is, why it seems to be something different in every RDF database, and how you can come to grips with those differences and query with confidence.

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Jeen is a principal engineer at metaphacts. He is one of the original designers and current project lead of Eclipse RDF4J, passionate about all things RDF and SPARQL, and has been a member of the Semantic Web community for donkey's years.