Approximation of OLAP queries on data warehouses
type: Dataset
description: We study the approximate answers to OLAP queries on data warehouses. We consider the relative answers to OLAP queries on a schema, as distributions with the L1 distance and approximate the answers without storing the entire data warehouse. We first introduce three specific methods: the uniform sampling, the measure-based sampling and the statistical model. We introduce also an edit distance between data warehouses with edit operations adapted for data warehouses. Then, in the OLAP data exchange, we study how to sample each source and combine the samples to approximate any OLAP query. We next consider a streaming context, where a data warehouse is built by streams of different sources. We show a lower bound on the size of the memory necessary to approximate queries. In this case, we approximate OLAP queries with a finite memory. We describe also a method to discover the statistical dependencies, a new notion we introduce. We are looking for them based on the decision tree. We apply the method to two data warehouses. The first one simulates the data of sensors, which provide weather parameters over time and location from different sources. The second one is the collection of RSS from the web sites on Internet.
identifier: NNT: 2013PA112091
issued: 2026-05-08T05:24:40.636781
language: en
modified: 2026-05-08T05:24:40.636785
contact point: Organization
  fn: CCSD
keyword: algorithme-dechantillonnage
keyword: approximate-query-answering
keyword: dependances-statistiques
keyword: distance-dedition
keyword: echange-de-donnees-olap
keyword: edit-distance
keyword: flux-de-donnees
keyword: infoeu-reposemanticsdoctoralthesis
keyword: infoinfo-ohcomputer-science-csother-csoh
keyword: modele-statistique
keyword: olap
keyword: olap-data-exchange
keyword: reponses-proches-de-la-requete
keyword: sampling-algorithm
keyword: statistical-dependencies
keyword: statistical-model
keyword: streaming-data
keyword: theses
landing page: https://theses.hal.science/tel-00905292

Approximation of OLAP queries on data warehouses
type: Distribution
format: HTML
issued: 2026-05-08T05:24:40.642936
modified: 2026-05-08T05:24:40.620733
access URL: https://theses.hal.science/tel-00905292

test_moissonnage_selune
type: Agent