XML: Structure Without Meaning

Note: Only covering enough XML concepts to understand RDF and OWL. Not a deep dive into XML itself.

XML stands for eXtensible Markup Language, designed to store and transport data & self-descriptive.

W3C recommends XML.

Remark: I find XML to be verbose and user-unfriendly though. But maybe it's one of the first universal and portable data transport format.

• Core: Syntax, rules, namespaces, properties.

• DOM: HTML DOM for XML

• XPath: CSS Selectors for XML

• XSLT: Template Engine for XML

• XQuery: SQL for XML

• XPointer: Fragment Identifiers for XML

• XLink: Hyperlinks for XML

Resources ​

Specs ​

• W3C XML 1.0 Spec - The definitive spec. Verbose but authoritative.

• W3C XML Namespaces - How XML avoids naming collisions using URIs. Critical for understanding how RDF serializes to XML.

Tutorials ​

• W3Schools XML Tutorial - Practical, example-driven intro. Good for syntax basics.

• MDN: XML Introduction - Brief, developer-focused overview.

In Semantic Web ​

• XML provides structure but no meaning: <name> could mean anything without external agreement. This is exactly the gap that RDF fills by adding URIs to every concept. See RDF: Meaning as Triples.