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OrientX: an Integrated, Schema- Based Native XML Database System - - PowerPoint PPT Presentation

Nov 30, 2022 348 likes •569 views

OrientX: an Integrated, Schema- Based Native XML Database System Meng Xiaofeng, Wang Xiaofeng, Xie Min, Zhang Xin, Zhou Junfeng School of information, Renmin University of China WISA2006 1 Introduction OrientX means: O riginal R UC I DK

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OrientX: an Integrated, Schema- Based Native XML Database System

Meng Xiaofeng, Wang Xiaofeng, Xie Min, Zhang Xin, Zhou Junfeng School of information, Renmin University of China WISA2006

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Introduction

  • OrientX means:

Original RUC IDKE Native XML Database – RUC: Renmin University of China – IDKE: Institute of Data and Knowledge Engineering – Native XML DataBase: Exposing a logical model

  • f storing and retrieving XML documents.

(non Native XML DataBase: for example, based on relation database)

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Outline

  • Architecture and Features
  • Storage and data management
  • Indexing Schema
  • Query processing
  • Conclusion and Future Work
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Architecture

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Features

  • Full support to XML Schema
  • Supporting XQuery1.0 and XPath2.0

Data Model

  • Various native storage techniques
  • Path index and value index
  • Multi-Query Processing strategies

based on native storage.

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Outline

  • Architecture and Features
  • Storage and data management
  • Indexing Schema
  • Query processing
  • Conclusion and Future Work
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Different storage granularities

  • Document:

– do not decompose the document, build index on it to direct the structure. – Query complexity and efficiency are restricted by the power of index.

  • Sub tree:

– decompose the document into sub trees according to storage space partition. – Persistent the structure in the tree. – save space

  • Node:

– decompose the document into nodes sequence , each node corresponding to a type (element, attribute, …). – May use too many links to persistent relation between nodes

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Storage Techniques in OrientX

CSB CEB Clustered BSB BEB Broad-first DB DSB DEB Depth-first Document- based SubTree- based Element- based

Implemented techniques are marked in red

One node is a record, through preorder traversing tree Like DEB, but each record is a sub-tree. The size of sub tree is close to physical page size One element is a record, but all node with the same tag name will be clustered-stored. Akin to DSB, each record is a sub tree. But all sub trees with the same structure are clustered store.

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Example-- Element based

r

a1 a2 t1 l1 l2 f2 f1 DEB CEB

r

a2 a1 l2 f2 l1 f1 t1 t1

r

a1 a2 f1 f2 l2 l1

Source doc

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Example-- Subtree based

r

a1 a2 t1 l1 l2 f2 f1

r

a1 a2 t1 l1 l2 f2 f1

DSB(Depth-first sub-tree based) CSB (clustered sub-tree based)

r

a1 a2 t1 l1 l2 f2 f1

DOC

Proxy node (virtual node)

Also have Proxy node

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Outline

  • Architecture and Features
  • Storage and data management
  • Indexing Schema
  • Query processing
  • Conclusion and Future Work
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Path index SUPEX: Index Architecture

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Features of SUPEX

  • Constructed based on DTD,Schema
  • Integrating path index with value indexes
  • Supporting Twig query efficiently
  • Supporting label path expressions

( bib//author)

  • Supporting the evaluation of value-based

condition predicates (//author[firstname = “jone”])

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Outline

  • Architecture and Features
  • Storage and data management
  • Indexing Schema
  • Query processing
  • Conclusion and Future Work
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Query processing

  • Navigation strategy

– Supporting XPath2.0 and XQuery1.0 – Combine continuous steps in one XPath into a single path. – Reform syntax tree into reduced execution plan. – Introducing the pipeline operator to XQuery process.

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1. Step 2. CondTreeNode 3. Path 4. ForVarBind 5. LetVarBind 6. FLWR 7. EleConstructor 8. AttrConstructor 9. BuiltInFun

  • 10. IfThenElse
  • 11. Quanlify
  • 12. SetOpt
  • 13. SortBy

Currently, Navigation Containing 13 operators:

Operators in Navigation

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General Steps to process XQuery

Parser and Translator

  • ptimizer

Evaluator Engine

XQuery Query Initial Query plan

  • ptimized Query plan
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The query plan

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Outline

  • Architecture and Features
  • Storage and data management
  • Indexing Schema
  • Query processing
  • Conclusion and Future Work
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Conclusion and Future Work

  • Conclusion:

– OrientX is an integrated, schema-based native XML database system. – It implements storing and querying xml data.

  • Future work:

– XQuery optimization. – Xml Update and Other XQuery processing engine.

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Thanks

Q&A☺

Welcome to our website http://idke.ruc.edu.cn to obtain more information about OrientX