Reformulating Aggregate Queries Using Views
نویسندگان
چکیده
We propose an algorithm to reformulate aggregate queries using views in a data integration LAV setting. Our algorithm considers a special case of reformulations where aggregates in the query are expressed as views over aggregates in the view definitions. Although the problem of determining whether two queries are equivalent is undecidable, our algorithm returns an equivalent reformulation if one exists.
منابع مشابه
Algorithms for Rewriting Aggregate Queries Using Views Algorithms for Rewriting Aggregate Queries Using Views Algorithms for Rewriting Aggregate Queries Using Views Algorithms for Rewriting Aggregate Queries Using Views
Queries involving aggregation are typical in database applications. One of the main ideas to optimize the execution of an aggregate query is to reuse results of previously answered queries. This leads to the problem of rewriting aggregate queries using views. Due to a lack of theory, algorithms for this problem were rather ad-hoc. They were sound, but were not proven to be complete. Recently we...
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Queries involving aggregation are typical in database applications. One of the main ideas to optimize the execution of an aggregate query is to reuse results of previously answered queries. This leads to the problem of rewriting aggregate queries using views. Due to a lack of theory, algorithms for this problem were rather ad-hoc. They were sound, but were not proven to be complete. Recently we...
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