Dependencies to Optimize Ontology Based Data Access

Mariano Rodriguez-Muro and Diego Calvanese

Proc. of the 24th Int. Workshop on Description Logics (DL 2011). Volume 745 of CEUR Workshop Proceedings, 2011.

Query answering in Ontology Based Data Access (OBDA) exploits the knowledge of an ontology's TBox to deal with incompleteness of the ABox (or data source). Current query-answering techniques with DL-Lite require exponential size query reformulations, or expensive data pre-processing. Also, these techniques present severe redundancy issues when dealing with ABoxes that are already (partially) complete. It has been shown that addressing redundancy is not only required for tractable implementations of decision procedures, but may also allow for sizable improvements in execution times. Considering the previous observations, in this paper we extend the results aiming at improving query answering performance in OBDA systems that were developed in [RodriguezCalvanese][AMW'11] for DL-LiteF , to the case where also role inclusions are present in the TBox. Specifically, we first show that we can characterize completeness of an ABox by means of dependencies, and that we can use these to optimize DL-LiteA TBoxes. Second, we show that in OBDA systems we can create ABox repositories that appear to be complete w.r.t. a significant portion of any DL-LiteA TBox. The combination of these results allows us to design OBDA systems based on DL-LiteA in which redundancy is minimal, the exponential aspect of query answering is notably reduced and that can be implemented efficiently using existing RDBMSs.

   title = "Dependencies to Optimize Ontology Based Data Access",
   year = "2011",
   author = "Mariano Rodriguez-Muro and Diego Calvanese",
   booktitle = "Proc. of the 24th Int. Workshop on Description Logics
(DL 2011)",
   pages = "367--377",
   volume = "745",
   publisher = "",
   series = "CEUR Workshop Proceedings,",
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