Query Stability in Data-aware Business Processes

Talk by Werner Nutt

Location: APB 3027
Start: 7. December 2016 at 2:50 pm
End: 7. December 2016 at 3:50 pm
Research group: Computational Logic
Event series: KBS Seminar
iCal

Organizations continuously accumulate data, often according to some business processes. If one poses a query over such data for decision support, it is important to know whether the query is stable, that is, whether the answers will stay the same or may change in the future because business processes may add further data.

We investigate query stability for conjunctive queries. To this end, we define a formalism that combines an explicit representation of the control flow of a process with a specification of how data is read and inserted into the database. We consider different restrictions of the process model and the state of the system, such as negation in conditions, cyclic executions, read access to written data, presence of pending process instances, and the possibility to start fresh process instances. We identify for which combinations of restrictions stability of conjunctive queries is decidable and provide encodings into variants of Datalog that are optimal with respect to the worst-case complexity of the problem.

Werner Nutt is a professor at the Faculty of Computer Science at the University of Bozen since 2005. Prior to this, he was reader at Heriot-Watt University, Edinburgh (2000-2005), visiting professor at the Hebrew University of Jerusalem, and research scientist at the German Research Center for Artificial Intelligence (DFKI) in Saarbruecken (1992-2000). His research interests are in knowledge representation and databases.