XML Glossary

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attribute

XML structural construct. A name-value pair within a tagged element that modifies certain features of the element. For XML, all values must be enclosed in quotation marks.

cascading style sheets (CSS)

Formatting descriptions that provide augmented control over presentation and layout of HTML and XML elements. CSS can be used for describing the formatting behavior of simply structured XML documents, but does not provide a display structure that deviates from the structure of the source data. See also Extensible Stylesheet Language.

CDATA section

XML structural construct. CDATA sections can be used to mark tags or reserved characters with quotation marks and thus prevent them from being interpreted. For this reason, the CDATA section is especially useful for escaping markup and script. The syntax for CDATA sections in XML is <![CDATA[ ... ]]>.

CDF

Channel Definition Format

Channel Definition Format (CDF)

An XML-based data format used in Microsoft® Internet Explorer 4.0 and later to describe Active Channel™ content and desktop components.

character data

XML structural construct. The text content of an element or attribute. XML differentiates this plain text from markup. In the XML OM, character data is stored in text nodes, which are implemented as DOMText objects.

character set

A mapping of a set of characters to their numeric values. For example, Unicode is a 16-bit character set capable of encoding all known characters; it is used as a worldwide character-encoding standard.

CIP

Commerce Interchange Pipeline

Commerce Interchange Pipeline (CIP)

An infrastructure used by Microsoft® Site Server Commerce Edition to exchange data between applications in XML over HTTP.

component

An object that encapsulates both data and code, and provides a well-specified set of publicly available services.

CSS

cascading style sheets

data binding

The process of associating the objects or controls of an application to a data source. A control associated with a data source is called a databound control. Data binding can be used to move XML-based data elements into HTML for display, essentially merging data into an HTML presentation template. The contents of a databound control are associated with values from a database. For example, a grid control that is bound to a Recordset object can be updated when the rows in the Recordset are updated. When new values are retrieved by the Recordset, new values are displayed in the grid.

data island

A proposed format for putting XML-based data inside HTML pages (<XML> or <SCRIPT language="XML">). HTML is used as the primary document or display format, and XML is used to embed data within the document.

Data Source Object (DSO)

Provides data, embedded by use of data binding, into an HTML page. Users can then sort and filter the data as they would a database, without needing to return to the server. DSOs supply data asynchronously to the page, similar to the way GIF images are displayed incrementally as they are transmitted.

data type

The type of content that an element contains: a number, a date, and so on. In XML, an author can specify an element's data type, for example, with a tokenized attribute type. Microsoft is working with the W3C to define a set of standard types that anyone can freely use. See also schema.

document element

The top-level element of an XML document; only one top-level element is allowed. The document element is a child of the document root.

Document Object Model (DOM)

The standard maintained by the W3C that specifies how the content, structure, and appearance of Web documents can be updated programmatically with scripts or other programs. The proposed object model for XML matches the Document Object Model for HTML so that script writers can easily learn XML programming. The XML DOM will provide a simple means of reading and writing data to and from an XML tree structure.

document root

The top-level node of an XML document; its descendants branch out from it to form the XML tree for that document. The document root contains the document element and can also contain a set of processing instructions and comments.

document type declaration

XML structural construct. A production within an XML document that contains or points to markup declarations that provide a grammar for a class of documents. This grammar is known as a Document Type Definition. The document type declaration can point to an external subset (a special kind of external entity) containing markup declarations, or can contain the markup declarations directly in an internal subset, or both. The DTD for a document consists of both subsets taken together. The syntax of the document type declaration is <!DOCTYPE content >.

Document Type Definition (DTD)

The markup declarations that describe a grammar for a class of documents. The DTD is declared within the document type declaration production of the XML file. The markup declarations can be in an external subset (a special kind of external entity), in an internal subset directly within the XML file, or both. The DTD for a document consists of both subsets taken together. See also schema.

DOM

Document Object Model

DSO

Data Source Object

DTD

Document Type Definition

EDI

Electronic Data Interchange

Electronic Data Interchange (EDI)

An existing format used to exchange data and support transactions. EDI transactions can be conducted only between sites that have been specifically set up with compatible systems.

element

XML structural construct. An XML element consists of a start tag, and end tag, and the information between the tags, which is often referred to as the contents. Elements used in an XML file are described by a DTD or schema, either of which can provide a description of the structure of the data.

entity

XML structural construct. A character sequence or well-formed XML hierarchy associated with a name. The entity can be referred to by an entity reference to insert the entity's contents into the tree at that point. The function of an XML entity is similar to that of a macro definition. Entity declarations occur in the DTD.

entity reference

XML structural construct. Refers to the content of a named entity. The name is delimited by the ampersand and semicolon characters; for example, &bookname; and &#x3C;. It is used in much the same way as a macro.

event handler

The code that is executed when an event occurs.

Extensible Linking Language (XLL)

An XML vocabulary that provides links in XML similar to those in HTML but with more functionality. Linking could be multidirectional, and links could exist at the object level rather than just at a page level.

Extensible Markup Language (XML)

A subset of SGML that provides a uniform method for describing and exchanging structured data in an open, text-based format, and delivers this data by use of the standard HTTP protocol. At the time of this writing, XML 1.0 is a World Wide Web Consortium Recommendation, which means that it is in the final stage of the approval process.

Extensible Stylesheet Language (XSL)

A language used to transform XML-based data into HTML or other presentation formats, for display in a Web browser. Differs from cascading style sheets in that it can present information in an order different from that in which it was received. XSL will also be able to generate CSS along with HTML. XSL consists of two parts, a vocabulary for transformation and the XSL Formatting Objects.

granular updating

Changing only an element of a page, rather than rebuilding the entire page. The new element is sent from the server to the client, which replaces the old element while leaving the rest of the page intact.

graphing

A very generalized way to represent certain data relationships.

ID

A special attribute type within the XML language. The ID attribute on the XML element provides a unique name, enabling links to that element using the IDREF attribute type. The value associated with the ID attribute must be unique within that XML document. IDs are currently declared with a DTD or schema.

markup

XML structural construct. Text in an XML document that does not represent character data: start tags, end tags, empty-element tags, entity references, character references, comments, CDATA section delimiters, DTDs, and processing instructions.

mixed content

XML structural construct. An element type has mixed content when elements of that type can contain character data, optionally interspersed with child elements. In this case, the types of the child elements can be constrained, but not their order or their number of occurrences.

namespace

A mechanism to resolve naming conflicts between elements in an XML document when each comes from a different vocabulary; it allows the commingling of like tag names from different namespaces. A namespace identifies an XML vocabulary defined within a URN. An attribute on an element, attribute, or entity reference associates a short name with the URN that defines the namespace; that short name is then used as a prefix to the element, attribute, or entity reference name to uniquely identify the namespace. Namespace references have scope. All child nodes beneath the node that specifies the namespace inherit that namespace. This allows nonqualified names to use the default namespace. See also RDF namespace.

NDATA

The literal string "NDATA" is used as part of a notation declaration. See also notation.

normalize

To collapse two or more adjacent text nodes in the document tree into one text node. This ensures that the tree structure will match tree structure generated when the document is stored and reloaded. The element object offers a normalize method.

notation

Usually refers to a data format, such as BMP. A notation identifies by name the format of unparsed entities, the format of elements that bear a notation attribute, or the application to which a processing instruction is addressed.

notation declaration

A notation declaration provides a name and an external identifier for a notation. The name is used in entity and attribute-list declarations and in attribute specifications. The external identifier is used for the notation, which can allow an XML processor or its client application to locate a helper application capable of processing data in the given notation.

OFX

Open Financial Exchange

Open Financial Exchange (OFX)

A data format used by personal-finance applications to communicate with financial institutions over the Web. Although it is currently described using SGML, OFX will soon be based on XML.

Open Software Description (OSD)

An XML-based data format for advertising and installing software components over the Internet.

OSD

Open Software Description

PI

processing instruction

processing instruction (PI)

XML structural construct. Instructions that are passed through to the application. The target is specified as part of the PI. The syntax for a PI is <?pi-name content?>.

RDF

Resource Definition Framework

RDF namespace

A specialized XML syntax designed to provide a limited form of RDF on the Web. See also Resource Definition Framework.

reference node

The reference node for a search context is the node that is the immediate parent of all nodes in the search context. Every search context has an associated reference node.

Resource Definition Framework (RDF)

An object model similar in function to an application programming interface (API), RDF can be used by developers to access the logical meaning of designated content in XML documents.

root element

Sometimes this term is used to refer to the document element but this is misleading, since the top-level element and the document root are not the same. Because of this ambiguity, use of the term "root element" is discouraged.

schema

A formal specification of element names that indicates which elements are allowed in an XML document, and in which combinations. A schema is functionally equivalent to a DTD, but is written in XML; a schema also provides for extended functionality such as data typing, inheritance, and presentation rules.

SGML

Standard Generalized Markup Language

Standard Generalized Markup Language (SGML)

The international standard for defining descriptions of structure and content of electronic documents. XML is a subset of SGML designed to deliver SGML-type information over the Web.

target

The application to which a processing instruction is directed. The target names beginning with "XML" and "xml" are reserved. The target appears as the first token in the PI. For example, in the XML declaration <?xml version="1.0"?>, the target is "xml".

text markup

Inserting tags into the middle of an element's text flow, to mark certain parts of the element with additional meta-information.

tokenized attribute type

Each attribute has an attribute type. Seven attribute types are characterized as tokenized: ID, IDREF, IDREFS, ENTITY, ENTITIES, NMTOKEN, and NMTOKENS.

Uniform Resource Identifier (URI)

The generic set of all names and addresses that refer to resources, including URLs and URNs. Defined in Berners-Lee, T., R. Fielding, and L. Masinter, Uniform Resource Identifiers (URI): Generic Syntax and Semantics. 1997. See updates to the W3C document RFC1738. The Layman-Bray proposal for namespaces makes every element name subordinate to a URI, which would ensure that element names are always unambiguous.

Uniform Resource Locator (URL)

The set of URI schemes that have explicit instructions on how to access the resource on the Internet.

Uniform Resource Name (URN)

A Uniform Resource Name identifies a persistent Internet resource.

updategram

XML generated by agents to notify the client of changes to data on the server, or vice versa; the agents could run on the middle tier to access multiple existing database management systems (DBMSs) and output XML.

URI

Uniform Resource Identifier

URL

Uniform Resource Locator

URN

Uniform Resource Name

valid XML

XML that conforms to the vocabulary specified in a DTD or schema.

vocabulary

See XML vocabulary.

W3C

World Wide Web Consortium

well-formed XML

XML that meets the requirements listed in the W3C Recommendation for XML 1.0: It contains one or more elements; it has a single document element, with any other elements properly nested under it; each of the parsed entities referenced directly or indirectly within the document is well-formed. A well-formed XML document does not necessarily include a DTD.

World Wide Web Consortium (W3C)

The international consortium founded in 1994 to develop standards for the Web. See W3C .

XLL

Extensible Linking Language

XML

Extensible Markup Language

XML Data Source Object (XML DSO)

A Data Source Object that provides a way to bind HTML elements directly to an XML data island. It assists developers in connecting to structured XML data and supplying it to an HTML page by using the data-binding facility of dynamic HTML. See also data island.

XML declaration

The first line of an XML file can optionally contain the "xml" processing instruction, which is known as the XML declaration. The XML declaration can contain pseudo-attributes to indicate the XML language version, the character set, and whether the document can be used as a standalone entity.

XML document

A data object that is well-formed, according to the XML recommendation, and that might (or might not) be valid. The XML document has a logical structure (composed of declarations, elements, comments, character references, and processing instructions) and a physical structure (composed of entities, starting with the root, or document entity).

XML DSO

XML Data Source Object

XML engine

Software that supports XML functionality on the client; Internet Explorer 4.0 and Internet Explorer 5 include XML engines.

XML Object Model (XML OM)

An API that defines a standard way in which developers can interact with the elements of the XML structured tree. The object model controls how users communicate with trees, and exposes all tree elements as objects, which can be accessed without any return trips to the server. The XML OM uses the W3C standard Document Object Model.

XML OM

XML Object Model

XML parser

A generalized XML parser reads XML files and generates a hierarchically structured tree, then hands off data to viewers and other applications for processing. A validating XML parser also checks the XML syntax and reports errors.

XML Query Language (XQL)

A term used to describe a set of extensions to XSL Patterns proposed to the W3C.

XML Schema

See schema.

XML vocabulary

The actual elements used in particular data formats. Channel Definition Format, for example, is a format for describing collections of pages and when these pages should be downloaded. Vocabularies, along with the structural relationships between the elements, can be defined in a DTD or a schema.

XML-Data

A proposal, submitted by Microsoft and others to the W3C, to define a number of common scalar data types that can be applied to elements. The XML-Data proposal includes the concept of XML schemas.

XQL

XML Query Language

XSL

Extensible Stylesheet Language

XSL Formatting Objects

A set of formatting semantics expressed as an XML vocabulary. Part of XSL.

XSL Patterns

Part of XSL that provides simple querying capability against an XML document. Internet Explorer 5 supports XSL Patterns with some of the extensions described in XML Query Language.