Optimal reflection of bidirectional view updates using information-based distance measures
2009 (English)In: Proceedings of the international workshop on logic in databases (LID 2009) / [ed] Leopoldo Bertossi and Henning Christiansen, Roskilde Denmark: Roskilde University , 2009, 57-70 p.Conference paper (Refereed)
When a database view is to be updated, there are generally many choices for the new state of the main schema. One way of characterizing the best such choice is to minimize the distance between the old state of the main schema and the new one. In recent work, a means of representing such distance based upon semantics was forwarded in which the distance between two states is measured by the the difference of information between the two, with the information of a state defined as the set of sentences from a particular set which hold on that state. This approach proved to be highly useful in identifying optimal reflections of insertions and to a lesser extent deletions, provided that the reflections were themselves insertions or deletions. In this work, that investigation is extended to bidirectional view updates – those which involve both insertion and deletion. It is shown that the definition of distance must be crafted more carefully in such situations. Upon so doing, a result is obtained which provides update reflections which are information optimal for insertion and deletion optimal with respect to tuples but not necessarily information.
Place, publisher, year, edition, pages
Roskilde Denmark: Roskilde University , 2009. 57-70 p.
, Computer science research report, ISSN 0109–9779 ; 127
IdentifiersURN: urn:nbn:se:umu:diva-40188OAI: oai:DiVA.org:umu-40188DiVA: diva2:398204
Proceedings of the International Workshop on Logic in Databases (LID 2009), Roskilde University, Denmark, October 29, 2009