A book by Elliotte Rusty Harold

A few words about author

Elliotte Rusty Harold is an internationally respected writer, programmer, and educator, both on the Internet and off. He got his start writing FAQ lists for the Macintosh newsgroups on Usenet and has since branched out into books, Web sites, and newsletters. He’s an adjunct professor of computer science at Polytechnic University in Brooklyn, New York. His Cafe con Leche Web site at cafeconleche.org has become one of the most popular independent XML sites on the Internet.

Subject covered by the book

The author speaks more to a website page author and less to a software programmer. XML is a markup language and not a programming language. The book covers the following aspects: you’ll learn how to validate documents against DTDs and schemas, how to author XML documents and make sure your XML is well formed, how to format your documents with CSS and XSL style sheets and how to build large documents from smaller parts using entities and XInclude and to connect documents with XLinks and XPointers.

The book is structured in five parts, starting with the simple things of introducing XML and ending with XML applications, and the data flows on more than 1150 pages.

XML is for structured data

XML is ideal for large and complex documents because the data is structured. You specify a vocabulary that defines the elements in the document, and you can specify the relations between elements. XML is a document format, a series of rules about what a document looks like. Comparing with HTML which has predefined elements, with XML you can define your own elements with the limitation that they are not completely arbitrary and have to follow a specific set of rules. An XML document has to be a well-formed document.

Document Type Definitions

The second part of the book covers how to validate XML documents against DTDs. A document type definition lists the elements, attributes, entities, and notations that can be used in a document, as well as their possible relationships to one another. It is set of declarations of rules for the structure of elements in an XML document.

Style Languages

To style the output of an XML document you can apply the rules of CSS, as used for HTML documents. But you can use the more powerful XSL (Extensible Stylesheet Language) which includes both a transformation language and a formatting language. The third part of the book covers both aspects, XSL Transformations (XSLT) and XSL Formatting Objects (XSL-FO) with examples to understand well how XSL works.

Supplemental Technologies

This part of the book is about XLinks, XPointers, XInclude and Schemas. XLink is similar with HTML link but is not restricted only to <A> (anchor) tag, which is a more flexible approach.
Schemas address a number of perceived limitations of DTDs, including a strange, non-XML syntax, namespace incompatibility, lack of data typing, and limited extensibility and scalability.

XML Application

This last part introduces more deeply in XHTML structure. XHTML 1.1 is much more practically extensible.
It is divided into abstract modules, each covering a specific area of functionality, such as tables, forms, images, structure, and text. The HTML elements and attributes are structured in 28 modules. For the most part, however, standard HTML pages require most of the modules. It’s when you begin mixing XHTML into your own XML applications that you can take advantage of smaller subsets of functionality.

Conclusions

If you want to learn how to use structured data with the help of XML and XHTML this book is a good start. Aspects are well explained and accompanied by detailed examples. Even it was released in 2004 is far from being obsolete.

References

XML Bible, 3rd edition - ISBN: 978-0-7645-4986-1