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Etude et implantation de l'extraction de requêtes fréquentes dans les bases de données multidimensionnelles.

Cheikh Tidiane Dieng 1
1 MIDI - Multimedia Indexation and Data Integration
ETIS - UMR 8051 - Equipes Traitement de l'Information et Systèmes
Abstract : The problem of mining frequent queries in a database has motivated many research efforts during the last two decades. This is so because many interesting patterns, such as association rules, exact or approximative functional dependencies and exact or approxi- mative conditional functional dependencies can be easily retrieved, which is not possible using standard techniques. However, the problem mining frequent queries in a relational database is not easy because, on the one hand, the size of the search space is huge (because encompassing all possible queries that can be addressed to a given database), and on the other hand, testing whether two queries are equivalent (which entails redundant support computations) is NP-Complete. In this thesis, we focus on Projection-Selection-Join (PSJ) queries, assuming that the database is defined over a star schema. In this setting, we define a pre-ordering (q ≤ q′) between queries and we prove the following basic properties : 1. The support measure is anti-monotonic with respect to ≤, and 2. Defining q ≡ q′ if and only if q ≤ q′ and q′ ≤ q, all equivalent queries have the same support. The main contributions of the thesis are, on the one hand to formally study properties of the pre-ordering and the equivalence relation mentioned above, and on the other hand, to prose a level-wise, Apriori like algorithm for the computation of all frequent queries in a relational database defined over a star schema. Moreover, this algorithm has been imple- mented and the reported experiments show that, in our approach, runtime is acceptable, even in the case of large fact tables.
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https://tel.archives-ouvertes.fr/tel-00642923
Contributor : Cheikh Tidiane Dieng <>
Submitted on : Saturday, November 19, 2011 - 8:45:38 PM
Last modification on : Thursday, December 17, 2020 - 12:14:38 PM
Long-term archiving on: : Monday, February 20, 2012 - 2:21:36 AM

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  • HAL Id : tel-00642923, version 1

Citation

Cheikh Tidiane Dieng. Etude et implantation de l'extraction de requêtes fréquentes dans les bases de données multidimensionnelles.. Base de données [cs.DB]. Université de Cergy Pontoise; Université Gaston Berger (SENEGAL), 2011. Français. ⟨tel-00642923⟩

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