Shape Expression Schemas

Shape Expression Schemas (ShEx) is a language for validating RDF data, developped within the ShEx W3C Community Group. ShEx allows to describe the desired structure as well as constraints to be satisfied by an RDF dataset, and to validate RDF data against these constraints.

I've been one of the main designers of ShEx 2.0, co-author of the ShEx specification, and am actively participating in the evolution of the language.


The Validating RDF Data book provides a comprehensive introduction to the ShEx and SHACL languages and contains numerous examples. Published by Morgan & Claypool in 2017.

The java API for ShEx validation, currently extended and maintained by Jérémie Dusart under my supervision.

A tool for inspecting RDF data quality based on ShEx validation that we are currently developping.


Creating and transforming RDF data, the Datacert project

The Datacert project is interested in Coq deep specification of privacy aware data integration. Within this project we design high-level languages and associated techniques for exporting relational or tree-structured data to high quality RDF.

Relational to RDF+ShEx data exchange: we introduced schema mappings tailored for translating relational data to RDF conformant to a ShEx schema.

The PhD thesis of Jose-Martin Lozano Aparicio is part of this project, under the direction of Sławek Staworko.

Hyperstreaming query evaluation

Hyperstreams are multiple streams with references to other hyperstreams.

We study the complexity of evaluation of queries defined by automata, and develop algorithms for approximate early query evaluation.

This is a work done within the PhD thesis of Momar Sakho, under the direction of Joachim Niehren.


Students and engineers


  • Momar Sakho, PhD candidate on Hyperstreaming evaluation. Director: Joachim Niehren. Supervisor: Iovka Boneva
  • Jose-Martin Lozano Aparicio, PhD candidate on Web data integration. Director: Slawek Staworko. Supervisor: Iovka Boneva


  • Jérémie Dusart. Works on implementing the java API and tools for Shape Expressions validation, under the supervision of Iovka Boneva