link: XML

XML Syntax

Basic XML Document

Here’s an example of a basic XML document that includes a declaration, elements, attributes, and nested elements:

<?xml version="1.0" encoding="UTF-8"?>
<bookstore>
    <book id="b1">
        <title>Understanding XML</title>
        <author>John Doe</author>
        <price currency="USD">29.99</price>
    </book>
    <book id="b2">
        <title>Advanced XML Features</title>
        <author>Jane Smith</author>
        <price currency="USD">35.99</price>
    </book>
</bookstore>

Attributes vs. Elements

Attributes provide additional information about elements. Comparing storage as attributes or elements affects accessibility and readability:

<!-- Using attributes -->
<employee id="E123" department="Finance"/>
 
<!-- Using elements -->
<employee>
   <id>E123</id>
   <department>Finance</department>
</employee>
 

Attributes are typically used for metadata, while elements handle data that could benefit from more structure.

Nested Elements

<university>
   <department name="Engineering">
       <faculty>Technology</faculty>
       <students>
           <student id="S1001">Alice</student>
           <student id="S1002">Bob</student>
       </students>
   </department>
</university>
 

XML allows for complex data structures through nested elements, ideal for hierarchical data such as academic records or organizational charts:

Special Characters and CDATA

CDATA sections are used to include special characters or unescaped data within XML documents:

<description>
   <![CDATA[
       This is a description text that can contain unescaped characters like <, >, or & without causing errors.
   ]]>
</description>
 

CDATA sections ensure that the data inside is treated purely as text, not XML markup.