- XML Elements
- Generic Identifiers
- Some Rules for Naming Elements
- Storing the Data in XML
- Parsed Character Data
- Bypassing Parsing with CDATA
- When to Use Attributes
- Classifying Attributes: Attribute Types
- Attribute Rules
- Well-Formedness Rules
- Creating a Well-Formed XML Document
- The Basics of Validation
- How Do Applications Use XML?
- An Overview of XML Tools
- Additional Resources
Storing the Data in XML
XML documents contain data that is stored in elements or attributes (which we will discuss later). This data is in the form of characters, and any valid Unicode character is also a valid character in XML. For example, all 26 letters of the English alphabet are characters, as are all the digits 0-9. All 33 characters of the Cyrillic alphabet are also valid characters.
The text in an XML document can be divided into two groups: character data and markup. Markup consists of the tags and syntax of XML components, whereas character data makes up the information stored in the document. In the example
<book> <title ISBN="0000-0000-0000">Using XML</title> </book>
the element tags and the attribute name are all considered markup, whereas the character data consists of the "0000-0000-0000" of the attribute value and the Using XML content of the title element. Character data in an XML document is divided into two types: Parsed Character Data (PCDATA) and Character Data (CDATA).