XML%20

1
XML Mediators

• Thitima Sirikangwalkul
• Wai Sum Mong

April 10, 2003
2
Agenda

• Problems and Solutions
• Introduction to XML
• XML Mediator Overview
• XML Mediator Examples

3
Problems

• Problem
• Storing and Processing Data Efficiently
• Past
• Single DBMS
• Present
• Isolated and heterogeneous database
• Integrated view needed

4
Solutions

• Wrapper-Mediator Approach
• Wrapper Interface
• Mediator Virtual Database
• eXtensible Markup Language (XML)
• Handle data from multiple sources
• Manage, Store, Query, and Present

5
XML Advantages

• Data exchange over Internet
• Representation standard
• Easy to create with Simple Editor
• Extensible, Flexible, and Simple
• System and Vendor Independent
• Self-Describable

6
Schemas

• DTD Vs XML Schema

XML Document
ltalbumgt lttitlegtTITLE Alt/titlegt ltsong id 1gtsong
1lt/songgt ltsong id 2gtsong 2lt/songgt lt/albumgt
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XML Mediator Architecture
Application
Application
Application
Mediator
Mediator
Mediator
Wrapper
Wrapper
Wrapper
DB1
DB2
XML Files
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XML Mediator Example
Find all Chicago customer names and their order
items
Application
Mediator
Retrieve customer names and id
Retrieve all cids and item names of orders
Wrapper
Wrapper
Order Database
Customer Database
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XML Mediator Example
Application
Mediator
Wrapper
Wrapper
Order Database
Customer Database
10
XML Mediator Basic Tasks

• Database Selection
• Query Translation
• Simple Query handled by Wrappers
• Result Merging
• Ranking algorithm

11
XML Mediation Systems

• E-XML Mediator
• EntireX Mediator

12
E-XML Mediator System Overview
13
E-XML Mediator
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E-XML Mediator

• During query processing,
• Determines the sources
• Determines the amount of sequential or parallel
  executions
• Determines the amount of query processing that
  can be offloaded onto the data sources

15
EntireX Mediator

• From Software AG
• Acts as a central hub of the XML-based
  information exchange
• Manages XML transactions over Internet
• Routes to the receiving application
• Converts message to appropriate format

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EntireX Mediator Architecture