©Silberschatz, Korth and Sudarshan10.1Database System Concepts W3C - The World Wide Web Consortium W3C - The World Wide Web Consortium

©Silberschatz, Korth and Sudarshan10.2Database System Concepts Evolving Standards HTML: is the lingua franca for publishing on the Web XHTML: an XML application with a clean migration path from HTML 4.01 CSS: Style sheets describe how documents are displayed XSL consists of three parts: XSLT, XPath, and XSL Formatting Objects. DOM: Document Object Model is a platform and language neutral API to access and update the content, structure, and style of a document SAX, Simple API for XML, stream-oriented SOAP: Simple Object Access Protocol communication protocol to allows programs to communicate via standard Internet HTTP

©Silberschatz, Korth and Sudarshan10.3Database System Concepts Application Program Interfaces There are two standard application program interfaces to XML data:  SAX (Simple API for XML)  Based on parser model, user provides event handlers for parsing events –E.g. start of element, end of element –Not suitable for database applications –Interesting format for data streams  DOM (Document Object Model)  XML data is parsed into a tree representation  Variety of functions provided for traversing the DOM tree  E.g.: Java DOM API provides Node class with methods getParentNode( ), getFirstChild( ), getNextSibling( ) getAttribute( ), getData( ) (for text node) getElementsByTagName( ), …  Also provides functions for updating DOM tree

©Silberschatz, Korth and Sudarshan10.4Database System Concepts W3C Activities--cont WAI: the Web Accessibility Initiative for people with disabilities MathML: Mathematical Markup Language SMIL: Synchronized Multimedia Integration Language to enable multimedia presentations on the Web SVG: Scalable Vector Graphics language for describing 2D graphics in XML

©Silberschatz, Korth and Sudarshan10.5Database System Concepts The Semantic Web The Semantic Web is an evolving extension of the World Wide Web in which web content can be expressed not only in natural language, but also in a format that can be read and used by automated tools, thus permitting people and machines to find, share and integrate information more easily. Resource Description Framework (RDF) describing metadata about Web resource---semantic web. Several data interchange formats, e.g. RDF/XML Standard Ontologies and the Web Ontology Language (OWL), that is actually a family for authoring ontologies