Since Google announced the internal use of Knowledge Graphs to improve search and organize information, their use and application has increased impressively.
Various technologies have been proposed to implement Knowledge Graphs: RDF-based triplestores are canonical in the Semantic Web, while in the graph databases context Labeled Property Graphs like Neo4J are also considered as another technology for Knowledge Graphs. Wikidata, a popular Knowledge Graph, offers RDF through its SPARQL query service, but its data model aligns closely with Property Graphs using qualifiers and references. The proposal of RDF-Star which is expected to become RDF 1.2 can bridge the gap between RDF and Property Graphs by allowing statements about statements.
The quality of data within these graphs is pivotal, often validated against expected data models or shapes to enhance accuracy. We will present some approaches that have been developed to describe and validate RDF like Shape Expressions (ShEx) or Shapes Constraint Language (SHACL). We will briefly describe them and show some differences.
In the case of Property Graphs, PGSchema was proposed, as well as other proposals like PShEx or ProGS, and more recently GQL offers a way to define typed graphs.
Wikidata adopted Entity Schemas, which are based on ShEx as well as its own property constraint system, and there is a proposal called WShEx.
This tutorial will explore different types of Knowledge Graphs and approaches for their validation. We will also review practical applications like inferring shapes from existing data and creating conforming subsets of Knowledge Graphs.
This is a half-day tutorial with the following topics:
We plan to devote the first slot to the first 3 items (knowledge graphs as well as Validating RDF technologies, ShEx and SHACL) which are more introductory, and the second slot for the rest of the items, which are more specialised.
Anyone interested in Semantic Web technologies and tools can attend this tutorial. Some rudimentary knowledge of RDF and Turtle is expected, although a short introduction to the RDF data model will be done.
To register, visit: ESWC'25
Examples and other material will be available at this repository