XML For Dummies

Lucinda Dykes started her career in a high-tech area of medicine, but left medicine to pursue her interests in technology and the Web. She has been writing code and developing Web sites since 1994, and also teaches and develops online courses — including the JavaScript courses for the International Webmasters Association/HTML Writers’ Guild at www.eclasses.org. Lucinda has authored, co-authored, edited, and been a contributing author to numerous computer books; the most recent include Dreamweaver MX 2004 Savvy (Sybex), XML for Dummies (3rd Edition, Wiley), Dreamweaver MX Fireworks MX Savvy (Sybex), XML Schemas (Sybex), and Mastering XHTML (Sybex). When she can manage to move herself away from her keyboard, other interests include holographic technologies, science fiction, and Bollywood movies. Ed Tittel is a 23-year veteran of the computing industry. After spending his first seven years in harness writing code, Ed switched to the softer side of the business as a trainer and talking head. A freelance writer since 1986, Ed has written hundreds of magazine and Web articles — and worked on over 100 computer books, including numerous For Dummies titles on topics that include several Windows versions, NetWare, HTML, XHTML, and XML. Ed is also Technology Editor for Certification Magazine, writes for numerous TechTarget Web sites, and writes a twice-monthly newsletter, “Must Know News,” for CramSession.com. In his spare time, Ed likes to shoot pool, cook, and spend time with his wife Dina and his son Gregory. He also likes to explore the world away from the keyboard with his trusty Labrador retriever, Blackie. Ed can be contacted at etittel@yahoo.com.

Introduction 1

About This Book 1

Conventions Used in This Book 2

Foolish Assumptions 3

How This Book Is Organized 4

Part I: XML Basics 4

Part II: XML and the Web 4

Part III: Building in Validation with DTDs and Schemas 5

Part IV: Transforming and Processing XML 6

Part V: XML Application Development 6

Part VI: The Part of Tens 7

Glossary 7

Icons Used in This Book 7

Where to Go from Here 8

Part I: XML Basics 9

Chapter 1: Getting to Know XML 11

XML (eXtreMely cooL) 12

Mocking up your own markup 12

Separating data and context 12

Making information portable 13

XML means business 13

Figuring Out What XML Is Good For 14

Classifying information 14

Enforcing rules on your data 15

Outputting information in a variety of ways 16

Using the same data across platforms 17

Beyond the Hype: What XML Isn’t 18

It’s not just for Web pages anymore 19

It’s not a database 20

It’s not a programming language 20

Building XML Documents 21

Chapter 2: Using XML for Many Purposes 23

Moving Legacy Data to XML 23

The Many Faces of XML 24

Creating XML-enabled Web pages 24

Print publishing with XML 25

Using XML for business forms 28

Incorporating XML into business processes 29

Serving up XML from a database 31

Alphabet Soup: Even More XML 31

Chapter 3: Slicing and Dicing Data Categories: The Art of Taxonomy 33

Taking Stock of Your Data 33

Looking at business practices and partners 34

Gathering some content 34

Checking whether a DTD or schema already exists 35

Searching for a schema repository 36

Breaking Down Data in Different Ways 37

Winnowing out the wheat from the chaff 38

Types of data that can be stored in XML 39

Developing Your Taxonomy 39

Testing Your Taxonomy 41

Using trial and error for the best fit 41

Testing your content analysis 42

Looking Ahead to Validation 43

Part II: XML and the Web 45

Chapter 4: Adding XHTML for the Web 47

HTML, XML, and XHTML 47

What HTML does best 48

The limits of HTML 49

Comparing XML and HTML 50

Using XML to describe data 51

The benefits of using HTML 53

The benefits of using XML 53

XHTML Makes the Move to XML Syntax 54

Making the switch 55

Every element must be closed 56

Empty elements must be formatted correctly 56

Tags must be properly nested 57

Case makes a difference 57

Attribute values are in quotation marks 58

Converting a document from HTML to XHTML 59

The Role of DOCTYPE Declarations 62

Chapter 5: Putting Together an XML File 65

Anatomy of an XML File 65

The XML declaration 67

Marking up your content 68

Playing by the Rules: Well-Formed Documents 74

Adding Style for the Web 76

Seeking Validation with DTD and XML Schema 78

Why describe XML documents? 79

Choosing between DTD and XML Schema 80

Chapter 6: Adding Character(s) to XML 83

About Character Encodings 84

Introducing Unicode 85

Character Sets, Fonts, Scripts, and Glyphs 87

For Each Character, a Code 88

Key Character Sets 89

Using Unicode Characters 91

Finding Character Entity Information 93

Chapter 7: Handling Formatting with CSS 95

Viewing XML on the Web with CSS 96

Basic CSS Formatting: CSS1 97

The Icing on the Cake: CSS2 98

Building a CSS Stylesheet 98

Adding CSS to XML 99

A simple CSS stylesheet for XML 101

Dissecting a simple CSS stylesheet 102

Linking CSS and XML 106

Adding CSS to XSLT 107

Part III: Building In Validation with DTDs and Schemas 109

Chapter 8: Understanding and Using DTDs 111

What’s a DTD? 112

When to use a DTD 113

When NOT to use a DTD 113

Inspecting the XML Prolog 114

Examining the XML declaration 115

Discovering the DOCTYPE 116

Understanding comments 116

Processing instructions 117

How about that white space? 117

Reading a DTD 118

Using Element Declarations 119

Using the EMPTY element type and the ANY element type 120

Adding mixed content 121

Using element content models 122

Declaring Attributes 123

Discovering Entities 125

General entities 126

Parameter entities 128

Understanding Notations 130

Calling a DTD 131

Internal DTDs 131

External DTDs 132

When to use an internal or external DTD 133

Chapter 9: Understanding and Using XML Schema 135

What’s an XML Schema? 136

So Many Datatypes, So Little Time 138

XML Prolog 139

Document Structures 141

Element declarations 141

Attribute declarations 144

Attribute groups 144

What about that white space? 145

Datatype Declarations 148

Simple datatypes 148

Complex datatypes 149

Defining constraints and value checks 149

Dealing with Entities, Notations, and More 150

Annotations 151

Deciding When to Use a Schema 152

Referencing XML Schema Documents 153

The inside view: Referencing a schema in an XML document 153

Calling for outside support: Referencing external schemas in your schema 153

Double-Checking Your Schemas and Documents 155

Chapter 10: Building a Custom XML Schema 157

Doing the Validity Rag 157

Step 1: Understanding Your Data 159

Step 2: Being the Root of All Structure: Elements 159

Step 3: Building Content Models 161

Step 4: Using Attributes to Shed Light on Data Structure 163

Step 5: Using Datatype Declarations to Define What’s What 164

Tricks of the Trade 167

Creating a Simple Schema 168

Using a Schema with an XML File in Word 2003 170

Chapter 11: Modifying an Existing Schema 173

Trading Control for Flexibility 174

Eliciting Markup from an XML Schema 174

Modifying a Schema 176

Using Datatypes Effectively 177

Using datatypes with data-intensive content 177

Using datatypes with text-intensive content 179

Making Elements Work Wisely and Well 180

Creating crafty content models 180

A matter of selection 181

Mixing up the order 183

Using Complex Datatypes 183

When XML Schemas Collide: Namespaces 185

Including External Data 188

Including/Excluding Document Content 188

Converting DTDs to Schemas 190

Part IV: Transforming and Processing XML 195

Chapter 12: Handling Transformations with XSL 197

The Two Faces of XSL 198

Xslt 198

Xsl-fo 200

XSL Stylesheets Are XML Documents 201

A Simple Transformation Using XSLT 202

An XSLT Stylesheet for Converting XML to HTML 202

The pieces of the stylesheet puzzle 205

Processing element content 207

Dealing with repeating elements 209

Creating an XSLT Stylesheet with XSLT Editors 210

Chapter 13: The XML Path Language 215

Why Do You Need Directions? 216

XPath document trees 217

Understanding XPath nodes 218

XPath Directions and Destinations 220

XPath Syntax 221

Some simple location paths 222

Adding expressions 223

Taking steps along the XPath 223

Looking at attributes 224

Going backward 224

Reversing direction 225

Null results 225

Getting back to your roots 226

XPath functions 226

Using XPath with XMLSpy 226

The Short Version 228

Child-axis abbreviations 229

Attribute-axis abbreviation 229

Predicate and expression abbreviations 229

Some more abbreviations 230

What’s New in XPath 2.0? 231

Where to Now? 233

Chapter 14: Processing XML 235

Frankly, My Dear, I Don’t Give a DOM 235

Keeping in touch with the family 238

Understanding DOM structure 238

What Goes In Must Come Out: Processing XML 240

So many processors, so little time 242

Which processor is right for you? 243

Part V: XML Application Development 245

Chapter 15: Using XML with Web Services 247

What’s Up with Web Services? 248

A Web Services Architecture 251

Transport: Moving XML messages 252

Packaging/Extensions: Managing information exchange 253

Description: Specifying services and related components 254

Discovery: Finding what’s available 255

Where Will Web Services Lead? 256

Chapter 16: XML and Forms 259

Collecting Information with Forms: The Basics 260

HTML Forms 260

XML Forms 261

XForms 261

InfoPath 267

Chapter 17: Serving Up the Data: XML and Databases 271

Using Databases with XML 272

Text-intensive XML 272

Data-intensive XML 273

Creating XML from Database Files 273

Using Word 2003 274

Using InfoPath 275

Using XMLSpy 278

Using XML with Access 2003 281

Chapter 18: XML and RSS 285

Introducing RSS 286

Sorting Out the Versions 286

RSS 0.9x 287

Rss 2.0/2.01 290

Rss 1.0 291

Validating an RSS Feed 295

Creating RSS Feeds 296

Get Syndicated! 297

Using an RSS Reader 298

Part VI: The Part of Tens 299

Chapter 19: XML Tools and Technologies 301

Creating Documents with Authoring Tools 301

Epic Editor 302

Turbo XML v2.4.1 303

XMetaL Author 4.5 303

XML Pro v2.0.1 303

XML Spy 2005 304

Checking Documents with Parser Tools 304

Ælfred 305

expat 306

Lark 306

Viewing with XML Browsers 307

Amaya 307

Internet Explorer 6 307

Mozilla 308

Firefox 1.0 308

Opera 308

Using XML Parsers and Engines 309

XML C Library for Gnome 309

Java XML Pack 310

Xerces 310

Employing Conversion Tools 311

HTML Tidy 311

Extensible Programming Script (XPS) 311

The Ultimate XML Grab Bag and Goodie Box 312

Microsoft does XML, too! 312

webMethods automates XML excellence 312

Chapter 20: Ten Top XML Applications 313

Xhtml = Xml + Html 314

XML Style Is a Matter of Application 314

Wireless Markup Language (WML) 314

DocBook, Anyone? 315

Mathematical Markup Language (MathML) 315

Scalable Vector Graphics (SVG) 316

Resource Description Framework (RDF) 316

Synchronized Multimedia Integration Language (SMIL) 317

Servin’ Up Web Services 317

XQuery 318

Create XML Applications with Zope 319

Chapter 21: Ten Ultimate XML Resources 321

XML’s Many and Marvelous Specs 321

An XML Nonpareil 322

XML in the Mail 323

Excellent XML Examples at zvon.org 323

XML News and Information 323

XML Training Options 324

Building a Bodacious XML Bookshelf 325

Studying XML for Certification 326

Serious Searches Lead to Success 327

Glossary 329

Index 347