Query optimization in the presence of limited access patterns
نویسندگان
چکیده
منابع مشابه
Query Containment in the Presence of Limited Access Patterns
In information-integration systems, sources may have access pattern limitations, i.e., they require values for certain attributes to return tuples. In this paper we study the following problem: given views with access pattern limitations, how to test whether the maximal answer to a conjunctive query (CQ) is contained in that to another CQ? Since a datalog program is necessary to compute the max...
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We consider the problem of querying data sources that have limited capabilities and can thus only be accessed by complying with certain binding patterns for their attributes. This is often the case, e.g., in the context of data on the web queryable via web forms as well as in legacy data wrapped in relational tables. In such contexts, computing the answer to a user query cannot be done as in a ...
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In information-integration systems, source relations often have limitations on access patterns to their data; i.e., when one must provide values for certain attributes of a relation in order to retrieve its tuples. In this paper we consider the following fundamental problem: can we compute the complete answer to a query by accessing the relations with legal patterns? The complete answer to a qu...
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In data applications such as information integration, there can be limited access patterns to relations, i.e., binding patterns require values to be specified for certain attributes in order to retrieve data from a relation. As a consequence, we cannot retrieve all tuples from these relations. In this article we study the problem of computing the complete answer to a query, i.e., the answer tha...
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ژورنال
عنوان ژورنال: ACM SIGMOD Record
سال: 1999
ISSN: 0163-5808
DOI: 10.1145/304181.304210