Node Labeling Schemes in XML Query Optimization: A Survey and Trends

Haw, Su-Cheng; Lee, Chien‐Sing

doi:10.4103/0256-4602.49086

Cited by 22 publications

(17 citation statements)

References 14 publications

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“…In the database field, where XML is essentially considered from a data-centric rather than a document-centric point of view, a number of labeling schemes are proposed especially to support structural queries (see [20] for a survey). In XRANK system [12], postings are again created only for the textual content directly under an element; however document identifiers are encoded using the Dewey ids so that the scores for the ancestor elements can also be computed without a propagation mechanism.…”

Section: Indexing Techniques For Xml Retrievalmentioning

confidence: 99%

“…For instance, since element ids are Dewey encoded, it may be hard to represent some elements in deeply nested XML documents. Another issue may be updating the Dewey codes when an XML document is updated (see [20] for a general discussion). Also, to our best knowledge, the performance of typical inverted index …”

Section: Performance Comparison Of Indexing Strategies: Focused Taskmentioning

confidence: 99%

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XML Retrieval Using Pruned Element-Index Files

Altıngövde

Atilgan

Ulusoy

2010

Lecture Notes in Computer Science

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Abstract. An element-index is a crucial mechanism for supporting content-only (CO) queries over XML collections. A full element-index that indexes each element along with the content of its descendants involves a high redundancy and reduces query processing efficiency. A direct index, on the other hand, only indexes the content that is directly under each element and disregards the descendants. This results in a smaller index, but possibly in return to some reduction in system effectiveness. In this paper, we propose using static index pruning techniques for obtaining more compact index files that can still result in comparable retrieval performance to that of a full index. We also compare the retrieval performance of these pruning based approaches to some other strategies that make use of a direct element-index. Our experiments conducted along with the lines of INEX evaluation framework reveal that pruned index files yield comparable to or even better retrieval performance than the full index and direct index, for several tasks in the ad hoc track.

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Section: Indexing Techniques For Xml Retrievalmentioning

confidence: 99%

Section: Performance Comparison Of Indexing Strategies: Focused Taskmentioning

confidence: 99%

XML Retrieval Using Pruned Element-Index Files

Altıngövde

Atilgan

Ulusoy

2010

Lecture Notes in Computer Science

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“…• Node-coding methods (see [25]) apply certain coding strategies to design codes for each node, in order for the relationship among nodes to be evaluated by computation. Into this category, we can classify, for example, the XML Indexing and Storage System (XISS) [10], XR-tree [13], Dewey numbering schema [14] or relative region coordinate [15].…”

Section: Related Workmentioning

confidence: 99%

Automata Approach to XML Data Indexing

Šestáková

Janoušek

2018

Information

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Abstract:The internal structure of XML documents can be viewed as a tree. Trees are among the fundamental and well-studied data structures in computer science. They express a hierarchical structure and are widely used in many applications. This paper focuses on the problem of processing tree data structures; particularly, it studies the XML index problem. Although there exist many state-of-the-art methods, the XML index problem still belongs to the active research areas. However, existing methods usually lack clear references to a systematic approach to the standard theory of formal languages and automata. Therefore, we present some new methods solving the XML index problem using the automata theory. These methods are simple and allow one to efficiently process a small subset of XPath. Thus, having an XML data structure, our methods can be used efficiently as auxiliary data structures that enable answering a particular set of queries, e.g., XPath queries using any combination of the child and descendant-or-self axes. Given an XML tree model with n nodes, the searching phase uses the index, reads an input query of size m, finds the answer in time O(m) and does not depend on the size of the original XML document.

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“…The three major techniques are the node index scheme [12,13,14], the graph index scheme [15,16,17], and the sequence index scheme [18,19,20,21,22]. The node index scheme relies on node labelling techniques [23] to encode the tree structure of an XML document in a database or in an inverted index. Graph index schemes are based on secondary indexes that contain structural path summaries in order to avoid join operations during query processing.…”

Section: Retrieval Of Structured Documentsmentioning

confidence: 99%

“…To support these relations, the requirement is to assign unique identifiers, called node labels, that encode the relationships between the nodes. Several node labelling schemes have been developed [23] but in the rest of the paper we use a simple prefix scheme, the Dewey Order encoding [56].…”

Section: Node-labelled Tree Modelmentioning

confidence: 99%