Description Logics for Data Access
Tutorial at the 24th AAAI Conference on Artificial Intelligence
Atlanta, Georgia, U.S.A., July 11-15, 2010
The tutorial illustrates recent developments in Description Logics (DLs) aimed at coupling DL
knowledge bases with relational data stores. For this coupling to be effective, two main issues
need to be addressed: (i) The language used to query the knowledge base needs to be much
more expressive than DL expressions, in particular the ability of expressing arbitrary joins as in
conjunctive queries (CQs) studied in databases is essential; (ii) Query answering should remain
tractable (PTIME or less) with respect to the size of the data. In order to address such issues, as
often happens in DL research, the language used to specify the knowledge base has to be
carefully designed to suitably balance expressiveness and computational complexity of reasoning.
However, differently from what typically happens in DL research, reasoning is not based on firstorder/
modal tableaux, but on chase techniques originally developed in databases for reasoning
over data dependencies. We will discuss DL languages designed for data access, and techniques
for reasoning in such DLs, focusing specifically on query answering. We also illustrate reasoning
tools that are available for such logics.
Time: Monday, July 12, 2:00 PM – 6:00 PM
Lectures with slides and demonstration
Researchers, Ph.D. Students, and Practitioners
Basic knowledge in first-order logic and relational
databases. Background in Description Logics is preferable, but not strictly necessary.
Outline of the tutorial content (draft)
- Introduction to the theory of conjunctive queries over relational databases
- DL knowledge bases and incomplete information
- Conjunctive query answering in DLs
- The DL-Lite family
- Query answering in the DL-Lite family: Compiling the knowledge base into the query
- DL-Lite for data integration: Accessing external data sources through mappings
- Approaches based on pre-processing of the data sources
- Beyond conjunctive queries: An Epistemic query language
Notes on DL-Lite.
Which is also available as the paper:
D. Calvanese, G. De Giacomo, D. Lembo, M. Lenzerini, A. Poggi, M. Rodriguez-Muro, and Riccardo Rosati.
Ontologies and databases: The DL-Lite approach. In Sergio Tessaris and Enrico Franconi, editors, Semantic Technologies for Informations Systems - 5th Int. Reasoning Web Summer School (RW 2009), volume 5689 of Lecture Notes in Computer Science, pages 255-356. Springer, 2009.
AAAI-10 Tutorial Forum web page
July 12, 2010