CDATA

When working with XML, there may be situations where you need to include character data that could potentially conflict with the syntax of the document. This is where CDATA sections come into play.

A CDATA section is a section of an XML document that is not parsed by the parser. Instead, the data inside the CDATA section is treated as character data.

The structure of a CDATA section is as follows:

<![CDATA[ 
    Your CDATA goes here. 
]]>

The opening <![CDATA[ and closing ]]> tags surround the character data that you want to include in the CDATA section.

Why use CDATA sections?

There are certain characters that have a special meaning in XML, such as <, >, &, and ". In order to include these characters as character data, you would need to use entity references or character references.

For example, if you wanted to include the string <hello> as character data in an XML document, you would need to write it as <hello>. This can get cumbersome if you have a lot of special characters that you need to include.

CDATA sections allow you to include character data without having to worry about escaping special characters. Any characters inside a CDATA section are treated as character data, regardless of whether they have a special meaning in XML.

How to use CDATA sections

Here's an example of how to use a CDATA section in an XML document:

<?xml version="1.0" encoding="UTF-8"?>
<root>
    <message>
        <![CDATA[
            This is some <b>bold</b> text that includes a & character.
        ]]>
    </message>
</root>

In this example, the message element includes some HTML markup as character data. Without the CDATA section, the < and > characters would be interpreted as XML tags, and the & character would need to be escaped as &.

With the CDATA section, the entire block of text is treated as character data, and special characters do not need to be escaped.

Conclusion

CDATA sections are a useful feature of XML that allow you to include character data without having to worry about escaping special characters. They can be particularly useful when including HTML or other markup as character data within an XML document.