Stratified division queries involving ordinal user preferences

ABSTRACT

In this paper, we are interested in taking preferences into account for a family of queries inspired by the relational division. A division query aims at retrieving the elements associated with a specified set of values and usually the results remain not discriminated. So, we suggest the introduction of preferences inside such queries with the following specificities: i) the user gives his/her preferences in an ordinal way and ii) the preferences apply to the divisor which is defined as a hierarchy of sets. Different uses of the hierarchy are investigated, which leads to queries conveying different semantics and the property of the result in terms of a quotient is studied. A special attention is paid to the implementation of such queries using a regular database management system and some experimental results illustrate the feasibility of the approach.

REFERENCES

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INDEX TERMS

Primary Classification:
  H. Information Systems
  H.2 DATABASE MANAGEMENT
      H.2.3 Languages

Additional Classification:
  H. Information Systems
  H.3 INFORMATION STORAGE AND RETRIEVAL
      H.3.3 Information Search and Retrieval

General Terms:
Algorithms, Experimentation, Languages

Keywords:
division, flexible querying, lexicographic order, ordinal preferences, quotient, top-k queries