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Ensuring License Compliance in Federated Query Processing

Benjamin Moreau 1 Patricia Serrano-Alvarado 1
1 GDD - Gestion de Données Distribuées
LS2N - Laboratoire des Sciences du Numérique de Nantes
Abstract : When two or more licensed datasets participate in the evaluation of a federated query, the query result must be protected by a license that is compliant with each license of the involved datasets. However, such a license does not always exist, and this leads to a query result that cannot be reused. We propose to deal with this issue during the federated query processing by discarding datasets of conflicting licenses. But then, a query with an empty result set can be obtained. To face this problem, we use query relaxation techniques. Our problem statement is, given a SPARQL query and a federation of licensed datasets, how to guarantee a relevant and non-empty query result whose license is compliant with each license of involved datasets? In a distributed environment, the challenge is to limit communication costs when the query relaxation process is necessary. In this paper, to detect and prevent license conflicts, we propose FLiQuE, a license aware query processing strategy for federated query engines. Experiments show that FLiQuE guarantees license compliance, and if necessary, can find relevant relaxed federated queries with a limited overhead in terms of execution time.
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Contributor : Benjamin Moreau <>
Submitted on : Tuesday, July 21, 2020 - 4:14:11 PM
Last modification on : Wednesday, August 5, 2020 - 3:43:39 AM


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  • HAL Id : hal-02904076, version 1


Benjamin Moreau, Patricia Serrano-Alvarado. Ensuring License Compliance in Federated Query Processing. 36ème Conférence sur la Gestion de Données – Principes, Technologies et Applications (BDA 2020), Oct 2020, (Online), France. ⟨hal-02904076v1⟩



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