Aggregate Queries over Conditional Tables

• Conditional tables have been identified long ago as a way to captureunknown or incomplete information. However, queries over conditionaltables have never been allowed to involve column functions such asaggregates. In this paper, the theory of conditional tables is extendedin this direction, and it is shown that a strong representation systemexists which has the closure property that the result of an aggregatequery over a conditional table can be again represented by a conditionaltable. As an application, the area of data warehouses is discussed,which is of increasing importance in many commercial applications thesedays, but which still lacks proper ways of handling incompleteinformation.

Ämnesord

NATURVETENSKAP  -- Data- och informationsvetenskap -- Datavetenskap (hsv//swe)

NATURAL SCIENCES  -- Computer and Information Sciences -- Computer Sciences (hsv//eng)

Nyckelord

Datavetenskap

Computer Science

Publikations- och innehållstyp

ref (ämneskategori)

rap (ämneskategori)