Xml articles

Design principles in XML part 2

admin — Fri, 24 Apr 2009 14:32:25 +0000

These goals have helped to shape a set of principles that are central to the effective use of XML. Although XML has certainly not invented these principles, it makes them more easy to apply.

We will look at these principles before examining the XML standard itself, in order to keep in mind the strategy we develop through the book.

XML functions on the basis of a number of key principles:

Separation of form and content

Authoring of documents within a constrained or ‘bridled’ structure, often referred to as a ‘schema’

Storage of structure, labelling and content in clear text rather than binary format, and created according to an agreed standard

‘Semantic’ labelling of content ‘chunks’

‘Keys’ to understanding the labelling accessible to all

The entirety of the rules regarding the structure of a text or document type, as well as additional functions including further processing, linking and management, should themselves be written in XML These goals have helped to shape a set of principles that are central to the effective use of XML. Although XML has certainly not invented these principles, it makes them moreeasy to apply. We will look at these principles before examining the XML standard itself, in order to keep in mind the strategy we develop through the book.XML functions on the basis of a number of key principles:

Separation of form and content

Authoring of documents within a constrained or ‘bridled’ structure, often referred to as a ‘schema’

Storage of structure, labelling and content in clear text rather than binary format, andcreated according to an agreed standard

‘Semantic’ labelling of content ‘chunks’

‘Keys’ to understanding the labelling accessible to all

The entirety of the rules regarding the structure of a text or document type, as well asadditional functions including further processing, linking and management, shouldthemselves be written in XML

Design principles in XML

admin — Wed, 22 Apr 2009 12:44:34 +0000

The team that developed the original XML standard set out ten goals by which they intended to evaluate the outcome of their work. Of these ten, five are of particular interest to us:

The standard should be usable directly over the Internet, using its existing infrastructure, protocols and standards.

XML must have a wide range of possible uses – it scope should not be not limited to Web pages, databases or text processing, but preferably cover all three and manymore besides.

It should be easy to write XML documents.

It should be easy to create applications that process XML documents. This is of particular significance in businesses where design-to-production time is important.

XML documents should be readable by humans, not just by machines. This hasmeant that the entirety of XML documents – content and ‘markup’, as we shall seelater – is written in plain text rather than a binary format. This also explains why werefer to XML files as ‘documents’.

Introdoction to XML

admin — Sat, 18 Apr 2009 15:44:12 +0000

We will start by examining XML’s origins briefly and, more importantly, the design principles and goals that its creation was intended to address. We will then examineXML itself and the range of related standards, and the principal means by which XMLcan be processed, particularly in the light of information management problems that wehave set out to address.

We should be clear on one point, however: this chapter is not intended to be a comprehensiveguide to the technical intricacies of XML, and no developer should launch intoany substantial project armed only with this information. The guide to further reading at the end of the book should help as a pointer to more in-depth material.

Having examined the range of standards, and to which problems they might be applied,we then aim to set out a high-level business case for the use of XML, and identify theimplications that its deployment throws up for management, thus tackling the coreconcerns of the book.