Encyclopedia of Database Systems

2018 Edition
| Editors: Ling Liu, M. Tamer Özsu

Uncertain Top-k Queries

  • Mohamed A. Soliman
Reference work entry
DOI: https://doi.org/10.1007/978-1-4614-8265-9_80686

Synonyms

Probabilistic ranking; Probabilistic top-k queries; Uncertain top-k queries

Definition

Given a relation R and a scoring function F that assigns a numeric score to each tuple in R, a top-k query returns the k tuples in R with the top ranks according to the scores computed by F. An uncertain top-k query is a top-k query where uncertainty (probabilistic) models are used to describe either R, F, or both R and F. Integrating the semantics of ranking and uncertainty models results in defining a probability distribution on the possible ranks of a given tuple in R according to F. Different formulations of uncertain top-k queries arise from such interplay between scoring and probabilistic measures. Query processing algorithms aim at minimizing the needed score and probabilistic computation by exploiting available data access paths and probabilistic early termination criteria.

Historical Background

Many uncertain/probabilistic data models adopt possible world semantics, where an...

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Recommended Reading

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Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Datometry Inc.San FranciscoUSA

Section editors and affiliations

  • Ihab Ilyas
    • 1
  1. 1.Cheriton School of Computer ScienceUniversity of WaterlooWaterlooCanada