Covering indexes for branching path queries

Kaushik, Raghav; Bohannon, Philip; Naughton, Jeffrey F.; Korth, Henry F.

doi:10.1145/564704.564707

Cited by 40 publications

(60 citation statements)

References 2 publications

(7 reference statements)

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“…Path index for branch query is another open issue. Although the F&B-Index [32] can be viewed as a covering index for branching path expression queries.…”

Section: Resultsmentioning

confidence: 99%

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Answering XML Queries Using Path-Based Indexes: A Survey

Wong

Tang

2006

World Wide Web

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The problem of answering XML queries using path-based indexes is to find efficient methods for accelerating the XML query with pre-designed index structures over the XML database. This problem received increasing interests and have been lucubrated in recent years. Regular path expression is the core of the XML query languages e.g., XPath and XQuery. Most of the state-of-the-art path-based XML indexes, therefore, hammer at how to efficiently answer the path-based XML queries. This paper surveys various approaches to indexing XML data proposed in the literature. We give a step by step analysis to show the evolution of index structures for XML path information, based on tree structures or more commonly, directed labeled graphs. For each approach, we first present the specific issue it aims to tackle, and then the proposed solution presented. Furthermore, construction, physical data storage and maintenance costs, are analyzed.

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“…Path index for branch query is another open issue. Although the F&B-Index [32] can be viewed as a covering index for branching path expression queries.…”

Section: Resultsmentioning

confidence: 99%

“…Forward and Backward-Index (F&B-Index) [32], defined directly from ideas proposed in [3], can be viewed as a covering index for branching path expression queries. The full F&B-Index (covers all path expression) is too large so they optimize it based on specially chosen subsets of path expressions.…”

Section: Related Workmentioning

confidence: 99%

Answering XML Queries Using Path-Based Indexes: A Survey

Wong

Tang

2006

World Wide Web

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“…Index graphs have been referred to with different names in the literature and they differ in the equivalence relations they employ to partition the nodes of the XML tree. An 1-index [21,24] considers as equivalent nodes in T that have the same incoming path from the root of T. An 1-index is a tree. 2 We define the index tree of T to be an 1-index of T without extents.…”

Section: Generating Path Queries From Index Treesmentioning

confidence: 99%

Evaluation Techniques for Generalized Path Pattern Queries on XML Data

Theodoratos

Souldatos

et al. 2010

World Wide Web

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Finding the occurrences of structural patterns in XML data is a key operation in XML query processing. Existing algorithms for this operation focus almost exclusively on path patterns or tree patterns. Current applications of XML require querying of data whose structure is complex or is not fully known to the user, or integrating XML data sources with different structures. These applications have motivated recently the introduction of query languages that allow a partial specification of path patterns in a query. In this paper, we consider partial path queries, a generalization of path pattern queries, and we focus on their efficient evaluation under the indexed streaming evaluation model. Our approach explicitly deals with repeated labels (that is, multiple occurrences of the same label in a query). We show that partial path queries can be represented as rooted dags for which a topological ordering of the nodes exists. We present three algorithms for the efficient evaluation of these queries. The first one exploits a structural summary of data to generate a set of path patterns that together are equivalent to a partial path query. 442 World Wide Web (2010) 13:441-474To evaluate these path patterns, we extend a previous algorithm for path-pattern queries so that it can work on path patterns with repeated labels. The second one extracts a spanning tree from the query dag, uses a stack-based algorithm to find the matches of the root-to-leaf paths in the tree, and merge-joins the matches to compute the answer. Finally, the third one exploits multiple pointers of stack entries and a topological ordering of the query dag to apply a stack-based holistic technique. We analyze our algorithms and perform extensive experimental evaluations. Our experimental results show that the holistic algorithm outperforms the other ones. Our approaches are the first ones to efficiently evaluate this class of queries in the indexed streaming model.

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“…The synopsis of a document, S D , is essentially a tree representation, as adopted in many existing works [8,10,12,21]. Users can easily apply one of the existing tools to generate a synopsis for an XML document.…”

Section: Xml Documents and Representationsmentioning

confidence: 99%