Skip to Main content Skip to Navigation
Preprints, Working Papers, ...

Possible and Certain Answers for Queries over Order-Incomplete Data

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.
Document type :
Preprints, Working Papers, ...
Complete list of metadatas
Contributor : Pierre Senellart <>
Submitted on : Wednesday, October 11, 2017 - 10:37:28 AM
Last modification on : Wednesday, October 14, 2020 - 4:20:28 AM

Links full text



Antoine Amarilli, Mouhamadou Lamine Ba, Daniel Deutch, Pierre Senellart. Possible and Certain Answers for Queries over Order-Incomplete Data. 2017. ⟨hal-01614571⟩



Record views