Structural Decomposition Methods: Key Notions and Database Applications

  • G. GrecoEmail author
  • N. Leone
  • F. Scarcello
  • G. Terracina
Part of the Studies in Big Data book series (SBD, volume 31)


Many difficult problems that are tractable when restricted to acyclic instances are good candidates to be solved efficiently whenever their structure is not precisely acyclic, but not far from that. This is the case for fundamental database problems such as answering conjunctive queries or counting the number of answers (without actually computing them). The chapter describes structural decomposition methods that guarantee tractability for all such problem instances whose associated hypergraphs have a small degree of cyclicity, called width. In particular, it focuses on the notion of hypertree width, by describing its properties and its applications to the database field, and covering queries with aggregate operators and some recent parallel and distributed implementations.



The work was supported by project “Ba2Know (Business Analytics to Know) Service Innovation - LAB”, No. PON03PE_00001_1 funded by the Italian Ministry of University and Research (MIUR), and by project “Smarter Solutions in the Big Data World (S2BDW)”, funded by the Italian Ministry for Economic Development (MISE) within the programme PON “Imprese e competitivitá” 2014–2020.


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Copyright information

© Springer International Publishing AG 2018

Authors and Affiliations

  • G. Greco
    • 1
    Email author
  • N. Leone
    • 1
  • F. Scarcello
    • 1
  • G. Terracina
    • 1
  1. 1.University of CalabriaRendeItaly

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