XML & Mediators Thitima Sirikangwalkul Wai Sum Mong April 10, 2003

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

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

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

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

Schemas DTD Vs XML Schema TITLE A song 1 song 2 XML Schema DTD XML Document

XML Mediator : Architecture Mediator Application Mediator DB1DB2 XML Files Wrapper

XML Mediator : Example Application Mediator Order Database Wrapper Customer Database Find all Chicago customer names and their order items Retrieve all cid ’ s and item names of orders Retrieve customer names and id

XML Mediator : Example Application Mediator Order Database Wrapper Customer Database

XML Mediator : Basic Tasks Database Selection Query Translation Simple Query handled by Wrappers Result Merging Ranking algorithm

XML Mediation Systems E-XML Mediator EntireX Mediator

E-XML Mediator – System Overview XQuery queries Web site Wrapper Web site (HTML pages) SQL Wrapper SQL Wrapper XQuery query SQL query SQL query XML Documents e-XML Mediator query RDBMS XDBMS

E-XML Mediator Administrates the mediator Registers wrapped data sources Query processing Communication interface Executes query Gives back the result

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

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

EntireX Mediator Architecture