Communicating with XML

1 Setting the Stage ....................................................................................... 1
1.1 Web Communications ....................................................................... 2
1.2 Markup .............................................................................................. 3
1.3 Markup Languages ............................................................................ 6
1.4 Document Type Defi nition ................................................................ 10
1.5 Types of XML Use ............................................................................ 11
1.5.1 Documents and Web Pages .................................................... 12
1.5.2 Other Primary Data ................................................................ 13
1.5.3 Metadata ................................................................................ 14
1.5.4 Data Interchange and Web Services ...................................... 15
1.6 Case Study: Communicating Via News Feeds .................................. 16
References .................................................................................................. 19
2 Fundamentals ........................................................................................... 21
2.1 Formal Grammars .............................................................................. 22
2.2 Processors and Applications .............................................................. 24
2.3 XML Documents ............................................................................... 27
2.3.1 Logical Structure ................................................................... 27
2.3.2 Physical Structure .................................................................. 33
2.3.3 Character Encoding ............................................................... 37
2.4 Declaring and Constraining Structures.............................................. 38
2.4.1 DTD and Markup Declarations ............................................. 38
2.4.2 Element Type Declarations .................................................... 40
2.4.3 Attribute List Declarations .................................................... 43
2.4.4 Entity and Notation Declarations .......................................... 46
2.4.5 XML Processor Treatment of Entities and References ......... 48
2.4.6 XML Schema ......................................................................... 52
2.4.7 RELAX NG ........................................................................... 61

2.5 Processing Models ............................................................................. 62
2.5.1 Stream Processing ................................................................. 63
2.5.2 Tree Processing ...................................................................... 64
2.5.3 Comparing Stream and Tree Processing................................ 66
References .................................................................................................. 66
3 Why Use XML? ........................................................................................ 69
3.1 Collaborative Standardization ........................................................... 70
3.1.1 Standardization at W3C ......................................................... 71
3.1.2 Sectoral Standardization ........................................................ 72
3.2 XML Family of Languages ............................................................... 73
3.2.1 Classifi cation of the XML Languages ................................... 74
3.2.2 XML Accessories .................................................................. 75
3.2.3 XML Transducers .................................................................. 76
3.2.4 XML Applications ................................................................. 77
3.3 Variety of Software ............................................................................ 84
3.4 Application-Independent Data Assets ............................................... 85
3.5 Web-Enabled Access ......................................................................... 86
3.6 Interoperability .................................................................................. 87
3.7 Case Study: Business Applications ................................................... 88
References .................................................................................................. 90
4 Document Management ........................................................................... 93
4.1 Structured Documents ....................................................................... 94
4.1.1 Structure Versus Content Versus Layout ............................... 94
4.1.2 Characteristics of Structured Document Management .......... 95
4.2 Transformations and XSLT ............................................................... 96
4.3 Rendering .......................................................................................... 100
4.3.1 Rendering with CSS .............................................................. 102
4.3.2 Rendering with XSL .............................................................. 104
4.4 Information Retrieval ........................................................................ 104
4.4.1 Indexing ................................................................................. 105
4.4.2 Retrieval Effectiveness and Ranking ..................................... 107
4.4.3 Querying XML Data .............................................................. 108
4.5 Case Study: Storing and Accessing Dictionaries .............................. 109
References .................................................................................................. 111
5 Data-Centric and Multimedia Components .......................................... 113
5.1 Data Types in XML Schema ............................................................. 114
5.1.1 Classifi cation of Data Types .................................................. 115
5.1.2 Facets ..................................................................................... 117
5.1.3 Type Hierarchy ...................................................................... 119
5.1.4 Example: Data Type Defi nitions
for the UK Government ......................................................... 120
5.2 Numeric Data .................................................................................... 121
5.3 Dates and Time .................................................................................. 122

5.4 Graphics and Multimedia Data.......................................................... 123
5.4.1 Scalable Vector Graphics ....................................................... 123
5.4.2 Multimedia ............................................................................ 130
5.5 Scientifi c Data ................................................................................... 135
5.5.1 Mathematical Data ................................................................. 135
5.5.2 Geospatial Data ..................................................................... 139
5.6 Data for Humanities and Social Sciences.......................................... 141
5.6.1 Electronic Books ................................................................... 142
5.6.2 Text Encoding Initiative......................................................... 143
References .................................................................................................. 145
6 Metadata ................................................................................................... 149
6.1 XML as Metadata and XML for Metadata ........................................ 150
6.2 Resource Discovery ........................................................................... 152
6.3 Dublin Core ....................................................................................... 153
6.4 Resource Management ...................................................................... 154
6.4.1 Learning Object Metadata ..................................................... 155
6.4.2 Metadata for Records Management ....................................... 156
6.4.3 Metadata for Preservation ...................................................... 158
6.5 RDF: Resource Description Framework ........................................... 158
6.6 Semantic Web .................................................................................... 162
References .................................................................................................. 166
7 Data Interchange ...................................................................................... 169
7.1 EDI .................................................................................................... 170
7.2 Frameworks for Business Interactions .............................................. 173
7.2.1 ebXML .................................................................................. 174
7.2.2 RosettaNet ............................................................................. 175
7.2.3 Industry-Specifi c Frameworks ............................................... 176
7.3 Web Services ..................................................................................... 178
7.4 Security in Data Interchange ............................................................. 179
7.5 The Status of Interchange Standards ................................................. 182
References .................................................................................................. 183
8 Adopting XML for Large-Scale Information ........................................ 185
8.1 Persistent Storage of XML Data ....................................................... 186
8.1.1 Special Characteristics and Requirements ............................. 186
8.1.2 XML Management Solutions ................................................ 191
8.1.3 Migration into XML Format.................................................. 194
8.2 When Not to Use XML ..................................................................... 195
8.2.1 Not to Replace Database Technology Universally ................ 196
8.2.2 Not to Replace Other Proven Technologies Arbitrarily ........ 196
8.2.3 Risks in the Development and Deployment
of New XML Applications .................................................... 197

8.3 Case Study: Government Applications ............................................. 198
8.3.1 The Case of the Finnish Parliament
and Government Ministries ................................................... 198
8.3.2 The Case of Massachusetts .................................................... 201
8.4 Conclusions ....................................................................................... 202
References .................................................................................................. 203
Appendix A Introduction to XHTML .......................................................... 207
Appendix B History of XML .......................................................................... 209
B.1 Origins of the Internet ............................................................................ 209
B.2 Origins of SGML ................................................................................... 210
B.3 From the Internet to the World Wide Web ............................................. 210
B.4 From SGML to XML ............................................................................. 211
Historical Readings .......................................................................................... 214
Appendix C Extended Backus-Naur Form (EBNF) ................................... 215
Index ..................................................................................................................... 217