XML and its kin

HTML (Hypertext Markup Language). A set of instructions, defined by the World Wide Web Consortium, for marking up text and graphics for presentation to a user by a Web browser. 

SGML (Standard Generalized Markup Language). An international standard for annotating electronic documents so they can be exchanged. HTML is a subset of SGML specifically designed for presenting material on the Web. XML is also a subset, and an extension, of SGML. SGML itself is considered too complex for facilitating most data exchanges. 

XML (Extensible Markup Language). A plain-text format for annotating a set of data with identifying information, using annotation terms of the user's choosing. 


Attribute. Additional defining characteristic that can be added to an element, such as the color of a vehicle. 

Class. A group of elements with a common theme. Elements such as hair and eye color can be elements in the person class.

Element. A short, basic classification of a block of data, such as author, vehicle, or footnote. Elements are encapsulated in angle brackets, for example: <vehicle>Ford</vehicle>.

Instance. A particular occurrence of an element or class, such as a red car.

Namespace. A vocabulary of keywords that make up an XML document's elements, attributes and other components. An application namespace categorizes keywords into sets to avoid semantic ambiguity.


Use these terms when talking shop with fellow XML administrators

Metalanguage. The descriptive names given to elements, classes, associations and other XML components.

Ontology. A detailed structure of an object, organization or other entity. An ontology describes the relationships among all the components, as well as their properties, functions, processes and restrictions. 

Taxonomy. A hierarchical classification of all the parts of an organization, object or other entity. A formal taxonomy adheres to standards-body definitions, classifications and rules of inference. Schemas may be derived from taxonomies. 

Semantic Web. A term coined by World Wide Web originator Tim Berners-Lee, the semantic Web is a network of data and services formatted in such a way that they can be used interactively by computers, in much the same way the World Wide Web is used by people today. A Semantic Web would require data and services to be tagged in common XML vocabularies, as well as hold computer-interpretable descriptions of the logic and context surrounding the data. To help, a Semantic Web-enabled computer could use the logic encapsulated in an Ontology Inference Layer and DAML markup languages to glean greater understanding of data.


Use these tools to corral your XML names into larger, more coherent sets

DTD (Document Type Definition). A method of defining elements within a document, which is now being superceded in many quarters by XML schemas.

Dublin Core. A broad set of general metadata terms with formal definitions, which XML administrators can use to help pick the best keywords words for schemas, useful as a common vocabulary if they want to share data sets with other parties. 

OWL (Web Ontology Language). A standard being developed by the World Wide Web Consortium for processing data contained in documents.

RDF (Resource Description Framework). An external set of descriptions that can be attached to a particular object, such as an audio file, image or text document.

XML Schema. A hierarchically structured collection of keywords used in an XML document or set of documents. A schema can implement part of an organization's taxonomy. The World Wide Web Consortium has rules for writing a schema that adheres to its syntax.


Some of these tools are still in the development stage and may facilitate more intelligent sharing and discovering of data.

DAML (DARPA Agent Markup Language). An XML language for representing ontologies. It extends RDF by the use of classes and subclasses. The W3C combined OIL and DAML for the DAML+OIL markup language, which includes aspects of both languages.

OIL (Ontology Inference Layer). A markup language to describe relationships with extensive reasoning capabilities.

XTM (XML Topic Maps). A standard XML vocabulary that captures the core subjects in a given domain along with relationships between those subjects.


These frameworks, composed of XML schemas and other tools, are built for specific industry or functional uses

ebXML (Electronic Business XML). A set of XML specifications for transacting business electronically over networks. The Business Process Specification Schema is used by ebXML as a common schema. 

MathML. A low-level XML specification for describing mathematics for machine-to-machine communication.

VoiceXML. A markup language for creating voice user interfaces.

Web Services. A collection of XML-formatted protocols to facilitate sharing of software-based services over the Web. Web service protocols include Simple Object Access Protocol (SOAP, for communications), Security Assertions Markup Language (SAML, for security), Universal Description, Discovery and Integration (UDDI, for discovering Web services), and Web Services Description Language (WSDL, for describing Web services).

XBRL (Extensible Business Reporting Language). An XML-based language for annotating financial and accounting information. 


DOM (Document Object Model). An interface for accessing an XML document or a Web page from programming and scripting languages.

SVG (Scalable Vector Graphics). An XML-based language for rendering graphical displays.

XForm. A model for creating XML-based forms that can be used across different platforms. 

XHTML (Extensible Hypertext Markup Language). A markup language for designing Web pages as XML documents. 

XLink (XML Linking Language). The specifications for describing links between XML documents using

XML parser. Software that extracts information from an XML document for use in other applications. A parser can also extract a schema from a document or validate an XML document as well formed against an existing schema or

XOP (XML-Binary Optimized Packaging). A process for compressing XML data sets into binary packaging in order to save storage space and bandwidth. 

XPath (XML Path Language). Rules for computers to automatically navigate to specific portions of XML documents.

XQuery (XML Query). A language for searching and formatting XML data in a database-style method.

XSD (XML Schema Infoset Model). A programmer's library for creating and modifying XML schemas. 

XSLT (Extensible Stylesheet Language Transformation). A set of rules to translate the contents of XML documents into other XML documents or into such other formats as Web pages or PDFs. 

Sources: Joseph Chuisano, associate, Booz Allen Hamilton Inc. of McLean, Va.; Steve Pepper, chief strategy officer, Ontopia; The XML Acronym Demystifier Web page ay www.xml-acronym-demystifier.org/; the World Wide Web Consortium; The Semantic Web by Michael Daconta, Leo Obrst and Kevin Smith (Wiley Publishing Inc.); and XML in a Nutshell, 3rd Edition, by Elliotte Rusty Harold and W. Scott Means (O'Reilly Media Inc.)

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