Guohui Xiao

Guohui Xiao is an assistant professor at the KRDB Research Centre for Knowledge and Data, Faculty of Computer Science, Free University of Bozen-Bolzano. His main research interests are knowledge representation, Semantic Web, database theory, and virtual knowledge graphs. He is currently coordinating the development of Ontop.

2021 Workshops and Tutorials: Integrating Data through Virtual Knowledge Graphs with Ontop

Recently, knowledge graphs have been successfully deployed to overcome the typical difficulties in accessing and integrating data stored in different kinds of sources. In particular, in the Virtual Knowledge Graph (VKG) approach, data is presented in the form of a graph, which is mapped to the underlying data sources, and query answering is based on advanced query transformation techniques. In this tutorial we illustrate the principles underlying the VKG approach, providing an overview of well-established algorithms and techniques, and we discuss relevant use-cases using VKGs. We also provide a step-by-step hands-on session, where participants can experiment on their own with the discussed technologies using the open-source VKG system Ontop ( and other open-source tools.