Talk: Willi Mann and Stefan de Lorenzo

On November 04, 2025, we had the pleasure to host a talk from Willi Mann and Stefan de Lorenzo on the Celonis Process Query Language (PQL) at the Department of Computer Science.

PQL is a powerful and intuitive data query language designed specifically for business users.

Together with the audience, Willi Mann and Stefan de Lorenzo explored PQL’s core data model with tables and a cycle-free join graph, PQL’s “column-oriented” language structure to simplify data retrieval and knowledge management, and filter-related key features like decoupled filtering, late filter application, and composability. Afterwards, Willi Mann and Stefan de Lorenzo gave an outline of the implementation and the underlying architecture, including an efficient software-level caching mechanism, and concluded with an outlook on PQL’s evolution to nativ OCDM query support. Finally, Willi Mann and Stefan de Lorenzo engaged in intensive discussions with the audience to clarify open questions.

This talk was announced as part of the DSP-MARS.

About the Presenters:

Willi Mann earned his Bachelor’s and Master’s degree in Computer Science at the University of Salzburg. After joining Nikolaus Augsten’s database research group at the Department of Computer Science in 2013, he earned his Doctoral degree in Computer Science in 2018. Currently, he is the Tech Lead of the Celonis PQL Team, which develops Celonis’ own query language PQL.

Stefan de Lorenzo also earned his Bachelor’s and Master’s degree in Computer Science at the University of Salzburg and work as a Software Engineer at the EMCO Corporation from 2012 to 2018. Afterwards, he returned to the University of Salzburg and earned his Doctoral degree in Computer Science under the supervision of Martin Held in 2021. In April 2023, he joined the Celonis PQL team.