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2002
ACM

On Propagation of Deletions and Annotations Through Views

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On Propagation of Deletions and Annotations Through Views
We study two classes of view update problems in relational databases. We are given a source database S, a monotone query Q, and the view Q(S) generated by the query. The first problem that we consider is the classical view deletion problem where we wish to identify a minimal set T of tuples in S whose deletion will eliminate a given tuple t from the view. We study the complexity of optimizing two natural objectives in this setting, namely, find T to minimize the side-effects on the view, and the source, respectively. For both objective functions, we show a dichotomy in the complexity. Interestingly, the problem is either in P or is NP-hard, for queries in the same class in either objective function. The second problem in our study is the annotation placement problem. Suppose we annotate an attribute of a tuple in S. The rules for carrying the annotation forward through a query are easily stated. On the other hand, suppose we annotate an attribute of a tuple in the view Q(S), what anno...
Peter Buneman, Sanjeev Khanna, Wang Chiew Tan
Added 08 Dec 2009
Updated 08 Dec 2009
Type Conference
Year 2002
Where PODS
Authors Peter Buneman, Sanjeev Khanna, Wang Chiew Tan
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