1 - XML Introduction

Overview

This blog is intended to accompany the study module; Advanced Web Technologies. Throughout each post, the aim is to work out pre-defined lab session while coming up with our own comments and remarks on the material/technologies being covered. XML is the primary focus of this module, as shall become obvious in the posts to come. The strength and importance of XML in today's world in undeniable, and albeit it being quite an old technology by today's fast-paced life standards, it is still very much widely used. XML is best described by W3 schools as "a software and hardware independent tool for carrying information", therefore; it is a means of transporting data. The aim of XML is to simplify the interactions with the data and facilitate the transport of data across multiple platforms.

For today's post, I will be answering the pre-assigned questions while referring to the provided examples and adding further comments.

Characteristics of XML

The defining characteristic of XML is that is used to store data. When storing this data, XML aims to define a structure for it. An XML document adheres to a user-defined structure. Through this structure, each document can be checked to confirm that the data is in the right structure.

XML also covers data of a hierarchical nature. A particular set of data might be best described in a pre-determined hierarchical structure and may also contain relationships. An example of this is demonstrated in the example defining an "advertisement" with elements such as "id", "status", "reference" and "comments" and their attributes and sub-hierarchies.

When defining the structure of your XML file, you are forced to instil unique labels for each item of data. This produces a described structure that is easily readable to humans, but at the same time is machine-friendly. The XML structure can be validated through a DTD or XSD file, thus ensuring that the file possesses the right structure, as shown in the "anthology" example.

Applications of XML

The simple and powerful nature of XML has seen it being adopted worldwide in a multitude of completely different systems. Although the systems may operate in a totally different manner, the storage and exchange of data is being exchange in a standard way: XML.

The provided examples illustrate this, by providing examples for systems such as an advertisement system, a book system (defining the structure of the book as appropriate ex: title, author, sections and paragraphs) and a country information bank.