An Analysis of the Current Development Stage of the eXtensible Markup Language (XML) and its Usage for Database Systems

MA-Thesis / Master von German Saueressig

Abstract:

The eXtensible Markup Language (XML) is receiving a great deal of attention from computing and Internet communities. This is mainly because of its ability to reduce obstacles in sharing data among diverse applications and databases by providing a common format for expressing data structure and content.

The scope of this project is to investigate the current stage of XML and its usage for database systems. In order to understand the XML database technology a general introduction to both database systems and XML is provided to the reader in chapter two and three. Chapter four and five deal with the methodology and findings of this project. These chapters rely on articles, case studies and surveys which are examined and evaluated. Finally, a conclusion and review chapter is included.

The analysis of the current adoption of XML among software developers revealed that in Spring 2001 more than one third of international developers already used XML. In 2001 they spent about 5.4% of their development time using XML. For 2002 it is predicted that they will spend an average of 9% of their development time using XML.

Concerning XML databases there are currently two major XML related database types available. These are native XML and XML enabled relational databases. Native XML databases are constructed to use the recommended XML standards to the most possible extent. Thereby, the XML document is the fundamental unit of storage. XML enabled relational databases are relational databases equipped with an additional layer to map XML content in to the relational tables. XML documents are only used as a means of transport between the database systems. Native XML databases are better suited for dealing with document structured content whilst XML enabled relational databases are more appropriate to handle data structured content such as numbers and pieces of text.

The implementation process of an XML related database system into an organisation requires the right management of change to be able to handle both the technology involved and the people affected by the database system. Therefore effective change management must cover the whole project life cycle from the formulation of the strategy to the achievement of the benefits.

Table of Contents:

	DISCLAIMER	II
	CONTENTS	III
	LIST OF FIGURES	VI
	LIST OF TABLES	VII
	ABSTRACT	VIII
	CHAPTER 1: INTRODUCTION	1
1.1	Background to this Study	1
1.2	Research Question	2
1.3	Task Settings and Objectives	3
1.4	Dissertation Sections	3
	CHAPTER 2: DATABASE ENVIRONMENT	5
2.1	The Database Approach	5
2.2	Three Level Architecture	6
2.3	Database Languages	8
2.4	Data Modelling and Database Design	9
2.5	Relational Data Model	11
2.6	Data Normalisation	14
	CHAPTER 3: RESEARCH TOPIC	17
3.1	A Brief History About XML	17
3.2	Concept of XML	18
3.2.1	Logical and Physical Structure of an XML Document	19
3.2.2	Document Type Definition	21
3.2.3	Style Sheets	21
3.3	Additional XML Features	23
3.4	The Acceptance of XML	24
3.5	Technological XML Developments	25
3.6	Drawbacks of XML	27
3.7	Where is it All Going to?	28
	CHAPTER 4: XML AND DATABASES	32
4.1	Methodology	32
4.2	XML Related Databases	33
4.3	The Problem of Finding the Right Database for XML Content	35
4.3.1	Documents Versus Data	36
4.4	Native XML Databases Versus XML Enabled Relational Databases	37
4.4.1	Data Modelling	38
4.4.2	Retrieval Speed and Searching	39
4.4.3	Static Versus Dynamic Structures	39
4.5	An Evaluation Checklist	40
4.6	Assessing the Current XML Database Adoption	42
4.7	A Native XML Database as a Base for a Content Management System	44
4.8	Conclusion	46
	CHAPTER 5: CHANGE MANAGEMENT WITHIN IT	50
5.1	Change Management	50
5.2	Types of Resistance and Constraints	52
5.3	Implementation of IT Projects	54
5.3.1	IT Management Process	56
5.4	Implementation of an XML Database	58
5.5	Conclusion	61
	CHAPTER 6: CONCLUSIONS AND REVIEW	64
6.1	Summary	64
6.2	Problems and Experiences	67
6.3	Further Studies	68
	APPENDIX 1: XML DOCUMENT AND XSLT STYLE SHEET EXAMPLE	69
	APPENDIX 2: XLINK AND XPOINTER EXAMPLE	71