License: Creative Commons Attribution 3.0 Unported license (CC BY 3.0)
When quoting this document, please refer to the following
DOI: 10.4230/LIPIcs.TIME.2017.4
URN: urn:nbn:de:0030-drops-79311
URL: http://dagstuhl.sunsite.rwth-aachen.de/volltexte/2017/7931/
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Amarilli, Antoine ; Ba, Mouhamadou Lamine ; Deutch, Daniel ; Senellart, Pierre

Possible and Certain Answers for Queries over Order-Incomplete Data

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LIPIcs-TIME-2017-4.pdf (0.6 MB)

Abstract

To combine and query ordered data from multiple sources, one needs to handle uncertainty about the possible orderings. Examples of such "order-incomplete" data include integrated event sequences such as log entries; lists of properties (e.g., hotels and restaurants) ranked by an unknown function reflecting relevance or customer ratings; and documents edited concurrently with an uncertain order on edits. This paper introduces a query language for order-incomplete data, based on the positive relational algebra with order-aware accumulation. We use partial orders to represent order-incomplete data, and study possible and certain answers for queries in this context. We show that these problems are respectively NP-complete and coNP-complete, but identify many tractable cases depending on the query operators or input partial orders.

BibTeX - Entry

@InProceedings{amarilli_et_al:LIPIcs:2017:7931,
  author =	{Antoine Amarilli and Mouhamadou Lamine Ba and Daniel Deutch and Pierre Senellart},
  title =	{{Possible and Certain Answers for Queries over Order-Incomplete Data}},
  booktitle =	{24th International Symposium on Temporal Representation and Reasoning (TIME 2017)},
  pages =	{4:1--4:19},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-052-1},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{90},
  editor =	{Sven Schewe and Thomas Schneider and Jef Wijsen},
  publisher =	{Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{http://drops.dagstuhl.de/opus/volltexte/2017/7931},
  URN =		{urn:nbn:de:0030-drops-79311},
  doi =		{10.4230/LIPIcs.TIME.2017.4},
  annote =	{Keywords: certain answer, possible answer, partial order, uncertain data}
}

Keywords: certain answer, possible answer, partial order, uncertain data
Collection: 24th International Symposium on Temporal Representation and Reasoning (TIME 2017)
Issue Date: 2017
Date of publication: 25.09.2017

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