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Views and Queries: Determinacy and Rewriting (2005)
| Content Provider | CiteSeerX |
|---|---|
| Author | Segoufin, Luc |
| Description | We investigate the question of whether a query Q can be answered using a set V of views. We first define the problem in information-theoretic terms: we say that V determines Q if V provides enough information to uniquely determine the answer to Q. Next, we look at the problem of rewriting Q in terms of V using a specific language. Given a view language V and query language Q, we say that a rewriting language R is complete for Vto-Q rewritings if every Q ∈Qcan be rewritten in terms of V ∈ Vusing a query in R, whenever V determines Q. While query rewriting using views has been extensively investigated for some specific languages, the connection to the information-theoretic notion of determinacy, and the question of completeness of a rewriting language, have received little attention. In this paper we investigate systematically the notion of determinacy and its connection to rewriting. The results concern decidability of determinacy for various view and query languages, as well as the power required of complete rewriting languages. We consider languages ranging from first-order to conjunctive queries. 1. In PODS |
| File Format | |
| Language | English |
| Publisher | ACM Press |
| Publisher Date | 2005-01-01 |
| Publisher Institution | Université De Paris Sud |
| Access Restriction | Open |
| Subject Keyword | Various View Result Concern Decidability Specific Language Little Attention Information-theoretic Notion View Language Rewriting Language Complete Rewriting Language Vto-q Rewriting Information-theoretic Term Query Language Enough Information |
| Content Type | Text |
| Resource Type | Article |
