Transcript A TREE BASED ALGEBRA FRAMEWORK FOR XML DATA …

A Prototype Implementation of
a Framework for Organising
Virtual Exhibitions over the
Web
Ali Elbekai, Nick Rossiter
School of Computing, Engineering and information
sciences
Northumbria University
Email: [email protected] ,
[email protected]
Overview
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Related Work
Prototype of Museum System
Architecture of System
Implementation of System
Related Work 1
• Vassil Vassilev 1999
– general description/technical specification of information
system for museum information processing
• Vassil Vassilev 2000
– publishing museum content over the Web, in archaeology,
in watermark images and in industrial heritage
• Nicholas Crofts 2003
– practical application of the CIDOC CRM in integrating a
large and diverse set of data sources.
• contain information relating to Geneva's architectural
and cultural heritage.
Related Work 2
• CIDOC/CIDOC CRM Special Interest Group
– 1994-2000 and 2000-2002
– define the underlying semantics of database
schemata and document structures
• for museum documentation
– support of good practice in
• conceptual modelling
• data transformation and data exchange
• information integration and mediation of heterogeneous
sources.
Related Work 3
• Bourret 2004
– XML (and its relations) have many facilities in common
with real databases such as
• storage (XML documents), schemas (DTDs, XML schema
languages) and programming interfaces (SAX, DOM, and JDOM)
• Wiederhold 1995
– wrapper mediator architecture
• uniform user interface
• query integrated views of heterogeneous sources
• Manolescu et al 2001
– query processor for different schema generation techniques
– materialized views over a virtual global schema
Related Work 4
• Elbekai & Rossiter 2005a
– algorithm as a technological solution for XQuery
interpreter generating
– XSL stylesheet for transforming XML query to SQL query
– XSL stylesheet in implementation of a framework for
organising virtual exhibitions
• Elbekai & Rossiter 2005b
– prototype of a framework for organising virtual exhibitions
• single XML Schema for specification of the common exhibition
• utilising contemporary information technologies for processing
XML data over the Web
• pan-European collaboration for organisation of virtual exhibitions
information
Prototype
• Assumes content published is extract of
CIDOC-compliant museum database
– easy standardisation and further dissemination
• Prototype system presented
– is built entirely using public domain stack of
technologies for processing XML data in Java
• J2SE, J2EE and additional XML and Web Services
packages
• functions as an entirely server-side Web application
executed by Tomcat server connected to a backend
database (one for each participating museum)
Entity Relationship Diagrams
• From Chen 1976, provide logical structure of
the databases for our proposed system
• Structure features
– Collection may relate to a number of Objects.
– Object may contain much Information such as Location,
Reference, Image, Documentation, Acquisition and
Collection.
– Exhibition has many Collections
– Exhibitions can be of different kinds
• public display, virtual exhibition or archive (type of exhibition)
– Institution has many Visitor groups, Exhibitions,
Collections, Objects, Information and one Address
Figure 1: Entity Relationship Diagram for the Museum System
Algorithm for Generating XML Stylesheet
• Use generated XSL stylesheet for transforming
XQueries to SQL queries
• For each XML schema/stylesheet
– build Document Object Model (DOM) tree
– pull nodes from DOM
– add SELECT clauses
• Generate new generic XML Stylesheet with
SQL code
Figure 2: An algorithm for generating XSL to transform
XQueries to SQL queries.
Figure 3: Generic XSL Stylesheet (XQuerytoSQLTrans.xsl)
for transforming XQuery to SQL
Architecture
• Web browser (Client)
– that can connect to the server
– to access the Java servlets
• the client can use PCs to run a Java servlet
• Middle Server
• DBMS server
– with SQL tables to provide database storage
Middle Server in more detail
• Middle server
– set of servers and internal network connecting them
– provides web server capable of accessing data
from DBMS and making it available to the client.
– choices include
• Web server, Web sever with servlets (Tomcat), SOAP
container (AXIS), a Virtual exhibition servlet, Java
Server Pages, HTML Pages and XSL stylesheets
• The communication protocol between the database and
the museum server could be JDBC
Figure 4: Architecture for the museum system
Implementation 1
• Integrated approach
• Step 1
– formulate an XQuery
– send query to web server tomcat with HTTP
• Step 2
– XSL Libraries transform XQuery to SQL
• Step 3
– SQL query string is generated
– Java servlet connects to database
– passes the SQL query string to database server over JDBC
Implementation 2
• Step 4
– Java servlet class retrieves information according
to SQL query string
– XSL stylesheet transforms retrieved data to XML
– sends output back to the client
• Result is shown on Tomcat server
Example for search and display of information 1
• After successful login
– client is able to search and display object
information.
• Step 1
– Client specifies and sends an XQuery such as
• For obj in <collection> Return <obj> Where
obj/<regis_Date> > 10.01.02
– to the Web server as a URL by using HTTP
Example for search and display of information 2
• Step 2
– Museum server parses and transforms request by
XSL stylesheet (XQuerytoSQLTran.xsl) on the
server and creates a SQL query string
• Step 3
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transformation is done
SQL query string generated
Java servlet is connected to database server
SQL query passed to the database server over
JDBC
Example for search and display of information 3
• Step 4
– query is executed
– database server returns report to museum server
– XSL stylesheet transforms report to HTML by
using the XSL stylesheet (GenXSLHTML.xsl)
– sends output back to the client.
– Result is shown on Tomcat server
Figure 5 Institutional information displayed
Figure 6 Institutional Information displayed on Tomcat server
Figure 7: Search and display objects
Figure 8: Objects displayed by the Client on Tomcat Server
Figure 9: Search and display information
Figure 10: Objects with registration date is 10.01.03
on Tomcat Server
Figure 11: Search and display information
Figure 12: Opening exhibition information on Tomcat Server
Contribution 1
• Prototype implementation of a framework for
organising virtual exhibitions
– Uses information provided by the collaborating
museums in the form of Web services.
– The museum content published by the museums is
• organised in a homogeneous virtual exhibition space by
an exhibition curator
• accessible from a single point of entry - the Virtual
Exhibition site.
Contribution 2
• The prototype
– assumes content published is an extract of a
CIDOC-compliant museum database,
• allowing easy standardisation and further dissemination.
– built entirely using public domain stack of
technologies
• for processing XML data in Java (J2SE, J2EE and
additional XML and Web Services packages).
– functions as an entirely server-side Web
application
• executed by Tomcat server connected to a backend
database.