A Framework for Using Materialized XPath Views in XML Query Processing

Balmin, Andrey; Özcan, Fatma; Beyer, Kevin; Cochrane, Roberta; Pirahesh, Hamid

doi:10.1016/b978-012088469-8.50009-7

Cited by 84 publications

(84 citation statements)

References 10 publications

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“…The rewriting is essentially a mapping from the output nodes of Q to the output nodes of V under which V ⊆ Q. When restricted to a single output node for each pattern or view, the mapping is unique, and the existence of a correct rewriting simply means V ⊆ Q. Balmin et al [3] addressed the problem of answering XPath queries using a single materialized view where, for the view, a combination of node references, typed data values, and full paths may be stored. However, the way in which a query is answered using the view is different: one can follow node references to go to the original document, so the original xml tree cannot be discarded.…”

Section: Related Workmentioning

confidence: 98%

Independence of Containing Patterns Property and Its Application in Tree Pattern Query Rewriting Using Views

Wang

Liu

2008

World Wide Web

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We show that several classes of tree patterns observe the independence of containing patterns property, that is, if a pattern is contained in the union of several patterns, then it is contained in one of them. We apply this property to two related problems on tree pattern rewriting using views. First, given view V and query Q, is it possible for Q to have an equivalent rewriting using V which is the union of two or more tree patterns, but not an equivalent rewriting which is a single pattern? This problem is of both theoretical and practical importance because, if the answer is no, then, to find an equivalent rewriting of a tree pattern using a view, we should use more efficient methods, such as the polynomial time algorithm of Xu and Özsoyoglu (2005), rather than try to find the union of all contained rewritings (which takes exponential time in the worst case) and test its equivalence to Q. Second, given a set S of views, we want to know under what conditions a subset S of S is redundant in the sense that for any query Q, the contained rewritings of Q using the views in S are contained in those using the views in S − S . Solving this problem can help us to, for example, choose the minimum number of views to be cached, or better design the virtual schema in a mediated data integration system, or avoid repeated calculation in query optimization. For the first problem, we identify several classes of tree patterns for which the equivalent rewriting can be expressed as a single tree pattern. For the second problem, we present necessary and sufficient conditions for S to be redundant with respect to some classes of tree patterns. For both problems World Wide Web (2009) 12:87-105 we consider extension to cases where there are rewritings using the intersection of multiple views and/or where a schema graph is present.

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Section: Related Workmentioning

confidence: 98%

Independence of Containing Patterns Property and Its Application in Tree Pattern Query Rewriting Using Views

Wang

Liu

2008

World Wide Web

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“…In [14], frequently submitted tree pattern queries are mined and maintained to answer new queries. [12] materializes XPath queries into views containing XML fragments, data values, full paths and node references to assist query processing. However, this work does not address the problem of speeding up the cache lookup process when the cache has a large number of views.…”

Section: Semantic Xml Query Cachingmentioning

confidence: 99%

“…XPath query containment has attracted a lot of attention these years [16−18] . [12][13][14][15] propose some frameworks and prototypes of organizing semantic cache in XML databases. [13] studies caching the result of XQuery queries at the client side.…”

Section: Semantic Xml Query Cachingmentioning

confidence: 99%

A Semantic Cache Framework for Secure XML Queries

Feng

2008

J. Comput. Sci. Technol.

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Secure XML query answering to protect data privacy and semantic cache to speed up XML query answering are two hot spots in current research areas of XML database systems. While both issues are explored respectively in depth, they have not been studied together, that is, the problem of semantic cache for secure XML query answering has not been addressed yet. In this paper, we present an interesting joint of these two aspects and propose an efficient framework of semantic cache for secure XML query answering, which can improve the performance of XML database systems under secure circumstances. Our framework combines access control, user privilege management over XML data and the state-of-the-art semantic XML query cache techniques, to ensure that data are presented only to authorized users in an efficient way. To the best of our knowledge, the approach we propose here is among the first beneficial efforts in a novel perspective of combining caching and security for XML database to improve system performance. The efficiency of our framework is verified by comprehensive experiments.

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“…The materialized view matching issue is also considered as the problem of answering queries using views. Tang et al developed different techniques for rewriting XPATH queries using materialized views (Tang et al 2008;Balmin et al 1997;Xu and Ozsoyoglu 2005;Arion et al 2007). Liu et al presented techniques for answering keyword queries using a minimal number of materialized views (Liu and Chen 2008).…”

Section: Introductionmentioning

confidence: 97%

“…Different types of databases are considered: the relational database (Zhou et al 2007;Luo 2007;Goldstein and Larson 2001;Mistry et al 2001;Gupta et al 1995;Blakeley et al 1986;Agrawal et al 2000;Re and Suciu 2007;Folkert et al 2005), the data warehousing (Phan and Li 2008;Park et al 2001;Baralis et al 1998;Yang et al 1997), the distributed database (Jiang et al 2008), and the XML database (Liu and Chen 2008;Tang et al 2008;Jiang et al 2008;Balmin et al 1997;Xu and Ozsoyoglu 2005;Arion et al 2007). The materialized view techniques are mainly focused on the following three issues: the materialized view selection, the materialized view matching, and the materialized view maintenance.…”

Section: Introductionmentioning

confidence: 97%

Optimization of generic progressive queries based on dependency analysis and materialized views

Zhu

Zuzarte

et al. 2014

Inf Syst Front

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Progressive queries (PQ) are a new type of queries emerging from numerous contemporary database applications such as e-commerce, social network, business intelligence, and decision support. Such a PQ is formulated on the fly in several steps via a set of inter-related step-queries (SQ). In our previous work, we presented a framework to process a restricted type of PQs. However, how to process generic PQs remains an open problem. In this paper, we develop a novel technique to efficiently process generic PQs based on materialized views. The SQs of an in-process PQ can utilize the results of previous SQs not only from the same PQ but also from other in-process and completed PQs. The key idea is to create a multiple query dependency graph (MQDG), which captures the data source dependency relationships among SQs from multiple PQs. A mathematic model is developed to estimate the benefit of keeping the result of an SQ as a materialized view (critical SQ/node) based on the MQDG. The kept materialized views are used to improve the performance of the future SQs. Strategies for constructing the MQDG and identifying the critical SQs for materialization by using the MQDG are presented. To manage the storage of the materialized views, we introduce two approaches -one employs a greedy method and the other adopts a dynamic programming (DP) based method. Strategies are also suggested to reduce the input problem size for the DP procedure. Experimental results demonstrate that our technique is quite promising in efficiently processing PQs.

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A Framework for Using Materialized XPath Views in XML Query Processing

Cited by 84 publications

References 10 publications

Independence of Containing Patterns Property and Its Application in Tree Pattern Query Rewriting Using Views

Independence of Containing Patterns Property and Its Application in Tree Pattern Query Rewriting Using Views

A Semantic Cache Framework for Secure XML Queries

Optimization of generic progressive queries based on dependency analysis and materialized views

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