XML

Introduction

• XML stands for ‘Extensible Markup Language’.

Definition

• XML is a markup language that defines a set of rules for encoding documents in a format that is both human-readable and machine-readable.
• XML is a versatile and widely adopted markup language that defines a set of rules for encoding documents in a standard format that is both human-readable and machine-readable.
• Its simplicity, extensibility, and interoperability make it a popular choice for a wide range of applications and use cases in the digital world.

Characteristics  

• Markup Language:
  • It uses tags to define the structure and semantics of data within a document.
  • Tags are enclosed in angle brackets < > and can be nested to represent hierarchical relationships between elements.
  • Elements can have attributes, which provide additional metadata or properties.
• Well-Formedness:
  • It documents must adhere to strict syntax rules to be considered well-formed. This includes having a single root element, properly nested elements, self-closing tags for empty elements, and attribute values enclosed in quotes.
  • Well-formed XML documents can be processed and validated by XML parsers.
• Extensibility:
  • It is designed to be extensible, allowing users to define custom markup languages and document structures using XML schemas or Document Type Definitions (DTDs). This enables developers to create domain-specific languages tailored to their specific needs.
• Interoperability:
  • It facilitates interoperability between different systems and platforms by providing a standardized format for representing structured data.
  • It documents can be exchanged between applications and processed by XML-aware software tools and libraries.
• Data Exchange:
  • It is commonly used for data interchange between heterogeneous systems, such as web services, databases, and applications.
  • These documents can represent a wide range of data types, including text, numbers, dates, and hierarchical structures.
• Transformation and Processing:
  • These documents can be transformed and processed using technologies such as XSLT (Extensible Stylesheet Language Transformations) and XPath (XML Path Language). XSLT allows developers to transform XML documents into different formats, while XPath provides a query language for navigating and selecting elements within XML documents.

Use/Applications

• It was designed to store and transport data, with a focus on simplicity, flexibility, and extensibility.
• It is widely used for representing structured data in various applications and industries, including web development, data exchange/interchange format(e.g., RSS, Atom), configuration files (e.g., XML configuration in Spring Framework), and document formats (e.g., XHTML, SVG).