Possible and certain answers for queries over order-incomplete data

Antoine Amarilli, Mouhamadou Lamine Ba, Daniel Deutch, Pierre Senellart

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

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.

Original languageEnglish
Title of host publication24th International Symposium on Temporal Representation and Reasoning, TIME 2017
EditorsSven Schewe, Jef Wijsen, Thomas Schneider
PublisherSchloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing
ISBN (Electronic)9783959770521
DOIs
StatePublished - 1 Oct 2017
Event24th International Symposium on Temporal Representation and Reasoning, TIME 2017 - Mons, Belgium
Duration: 16 Oct 201718 Oct 2017

Publication series

NameLeibniz International Proceedings in Informatics, LIPIcs
Volume90
ISSN (Print)1868-8969

Conference

Conference24th International Symposium on Temporal Representation and Reasoning, TIME 2017
Country/TerritoryBelgium
CityMons
Period16/10/1718/10/17

Keywords

  • Certain answer
  • Partial order
  • Possible answer
  • Uncertain data

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