License: 
Creative Commons Attribution 4.0 International license (CC BY 4.0)
When quoting this document, please refer to the following
DOI: 10.4230/LIPIcs.ICDT.2023.23
URN: urn:nbn:de:0030-drops-177659
URL: http://dagstuhl.sunsite.rwth-aachen.de/volltexte/2023/17765/
Amezian El Khalfioui, Aziz ;
Wijsen, Jef
Consistent Query Answering for Primary Keys and Conjunctive Queries with Counting
Abstract
The problem of consistent query answering for primary keys and self-join-free conjunctive queries has been intensively studied in recent years and is by now well understood. In this paper, we study an extension of this problem with counting. The queries we consider count how many times each value occurs in a designated (possibly composite) column of an answer to a full conjunctive query. In a setting of database repairs, we adopt the semantics of [Arenas et al., ICDT 2001] which computes tight lower and upper bounds on these counts, where the bounds are taken over all repairs. Ariel Fuxman defined in his PhD thesis a syntactic class of queries, called Cforest, for which this computation can be done by executing two first-order queries (one for lower bounds, and one for upper bounds) followed by simple counting steps. We use the term "parsimonious counting" for this computation. A natural question is whether Cforest contains all self-join-free conjunctive queries that admit parsimonious counting. We answer this question negatively. We define a new syntactic class of queries, called Cparsimony, and prove that it contains all (and only) self-join-free conjunctive queries that admit parsimonious counting.
BibTeX - Entry
@InProceedings{amezianelkhalfioui_et_al:LIPIcs.ICDT.2023.23,
author = {Amezian El Khalfioui, Aziz and Wijsen, Jef},
title = {{Consistent Query Answering for Primary Keys and Conjunctive Queries with Counting}},
booktitle = {26th International Conference on Database Theory (ICDT 2023)},
pages = {23:1--23:19},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-270-9},
ISSN = {1868-8969},
year = {2023},
volume = {255},
editor = {Geerts, Floris and Vandevoort, Brecht},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/opus/volltexte/2023/17765},
URN = {urn:nbn:de:0030-drops-177659},
doi = {10.4230/LIPIcs.ICDT.2023.23},
annote = {Keywords: Consistent query answering, primary key, conjunctive query, aggregation, counting}
}
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Keywords: |
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Consistent query answering, primary key, conjunctive query, aggregation, counting |
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Collection: |
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26th International Conference on Database Theory (ICDT 2023) |
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Issue Date: |
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2023 |
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Date of publication: |
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17.03.2023 |
