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Structural Query For Multiversion XML Document Based On Index

Posted on:2007-05-11Degree:MasterType:Thesis
Country:ChinaCandidate:Z DingFull Text:PDF
GTID:2178360218950948Subject:Computer applications
Abstract/Summary:PDF Full Text Request
The main purpose of version management of XML documents is to store a sequence of updates of an XML document efficiently so as to reduce the storage costs, retrieve previous versions rapidly, and use complex functions to search all the versions.This paper mainly focuses on how to break through the limitation of the retrieve of version and conduct complicated structure inquiry to the discretionary version of XML documents. Centering on this theme, this paper will discuss from three aspects: numbering schema, index, and structural join.The main contributions of this dissertation include: Firstly, discuss XML numbering schema, take advantage of both temporal and spatial concepts to create position number, and version number for every node in the XML tree structures; retrieve a particular previous version of the XML document version according to its version numbers; while position number is used to maintain structural relationship between nodes. Directed against the defects from current numbering schema towards updating support, we introduce the pattern of coding subtree with floating point numbers which supports the updating of versions better, and also has an important influence on the maintaining of index mentioned later.Secondly, introduce index mechanism that supports multiple versions XML, which is based upon numbering schema. It will be easier and more quick to obtain node list with version information for inquiry under this index mechanism. Optimize inquiry by means of skipping nodes which don't participate in structural joining.Lastly, the paper analyzes and researches on structural join algorithm thoroughly and focuses on improving the three classical algorithm of structural joining in order to support the multi-version XML query function. Among them, ADB-MV utilizes the new index mechanism and proves to have owned better functions than the original two.
Keywords/Search Tags:XML, multiversion XML, query processing, structural join, Xquery
PDF Full Text Request
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