Bertram Ludäscher: On Queries and the Expressive Power of Query Languages

Title: On Queries and the Expressive Power of Query Languages
(or: What you always wanted to know about query languages but never dared to ask)
Session Lead: Dr. Bertram Ludäscher
Time: 10 am – 11 am, Thursday, 2022-01-27
Location: Zoom


So you’ve learned that the XML model provides a “more flexible” way to represent all sorts of data, from structured to semistructured and even unstructured data (removing the shackles of the rigid relational model!). You have been told that RDF is a simple, flexible data model to represent complex situations, relationships, and other things of interest (while also being appropriately abstract!!). You have studied object-oriented databases for better abstraction and graph databases for its natural beauty to represent knowledge graphs. And of course you’ve sipped from the Cool-Aid of the NoSQL evangelists and are in awe about the powerful capabilities of NoSQL databases. Abandon all hope, ye who enter here. In this presentation I will remind us how the relational model can be used to represent different types of data, thank you very much. More importantly I will present the notion of “expressive power” of query languages which allows us to study more conceptual and foundational aspects of information modeling, i.e., the classes of questions (queries) expressible by a language. Everyone is welcome (especially XML and RDF enthusiasts 🙂

Readings: [Box-Folder]