Abstract:
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In this paper we present a new approach that handles query
containment problems by expressing them as a view updating
problem. Since this approach is independent of any particular view
updating method, it provides a general framework that joins research
efforts in both the query containment checking and view updating
fields. In particular, the larger development of current view updating
technology allows us to check properly query containment when
considering negative-derived literals or integrity
constraints. Existing methods for query containment checking that deal
with these cases do not check actually containment but another related
property called uniform containment, which is a sufficient but not
necessary condition for containment. Therefore, an important outcome
of our proposal is that, to the best of our knowledge, it is the first
approach that checks true query containment instead of uniform
query containment in the presence of negation and integrity
constraints. |