Consistency preserving updates in deductive databases

Abstract

Several problems may arise when a deductive database is updated. The problems that are addressed in this paper are those of integrity constraint maintenance and view updating. In this sense, we define a method that tackles both problems in an integrated way and that it is sound and complete. We also propose an architecture for our method to deal with both problems efficiently. Improvement of efficiency during the integrity constraint maintenance is based on a technique that determines the order in which integrity constraints should be handled. This technique is based on the generation of a graph that states the relationships between potential violations and potential repairs of integrity constraints. This order reduces significantly the number of times that each integrity constraint has to be considered after any integrity constraint repair. To improve efficiency during view updating, we propose to perform an initial analysis of the update request to reduce the number of database accesses and to explore only the relevant alternatives that may lead to valid solutions of an update request. Furthermore, a detailed comparison considering effectiveness and efficiency issues is also provided with respect to other methods that also deal with integrity constraint maintenance and view updating.