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The Extensible Markup Language (XML) is a W3C-recommended general-purpose markup language for creating special-purpose markup languages, capable of describing many different kinds of data. It is a simplified subset of SGML. Its primary purpose is to facilitate the sharing of data across different systems, particularly systems connected via the Internet. Languages based on XML (for example, Geography Markup Language (GML), RDF/XML, RSS, MathML, Physical Markup Language (PML), XHTML, SVG, MusicXML and cXML) are defined in a formal way, allowing programs to modify and validate documents in these languages without prior knowledge of their form. The World Wide Web Consortium (W3C) is an international consortium where member organizations, a full-time staff, and the public work together to develop standards for the World Wide Web. ...
A specialized markup language using SGML is used to write the electronic version of the Oxford English Dictionary. ...
DATA (Debt, AIDS, Trade, Africa) was established in 2002 by Bono (Paul Hewson) of the Rock band U2, and Bobby Shriver, along with activists from the Jubilee 2000 Drop the Debt Campaign, as an organisaton focused on Justice, not charity. ...
The Standard Generalized Markup Language (SGML) is a metalanguage in which one can define markup languages for documents. ...
The Geography Markup Language (GML) utilises XML to express geographical features. ...
Resource Description Framework (RDF) is a family of specifications for a metadata model that is often implemented as an application of XML. The RDF family of specifications is maintained by the World Wide Web Consortium (W3C). ...
RSS is a family of XML file formats for Web syndication used by (among other things) news websites and weblogs. ...
Mathematical Markup Language (MathML) is an application of XML for representing mathematical symbols and formulae, aimed at integrating them into World Wide Web documents. ...
Physical Markup Language (PML) is a markup language based on XML for communicating a description of physical environments and the objects within them, their relationships to you, each other and the space. ...
The Extensible HyperText Markup Language, or XHTML, is a markup language that has the same expressive possibilities as HTML, but a stricter syntax. ...
Scalable Vector Graphics (SVG) is an XML markup language for describing two-dimensional vector graphics, both static and animated. ...
MusicXML is an open, XML-based music notation file format. ...
cXML is a streamlined protocol intended for consistent communication of business documents between procurement applications, e-commerce hubs and suppliers. ...
History
By the mid-1990s some practitioners of SGML had gained experience with the then-new World Wide Web, and believed that SGML offered solutions to some of the problems the Web was likely to face as it grew. Jon Bosak argued that the W3C should sponsor an "SGML on the Web" activity. After some resistance he was authorized to launch that activity in mid-1996, albeit with little involvement by or support from the W3C leadership. Bosak was well-connected in the small community of people who had experience both in SGML and the Web. He received support in his efforts from Microsoft. The 1990s refers to the years 1990 to 1999; the last decade of the 20th Century, but in an economical sense The Nineties is often considered to span from the fall of the Berlin Wall in November 1989 to the September 11 attacks in 2001. ...
The Standard Generalized Markup Language (SGML) is a metalanguage in which one can define markup languages for documents. ...
Graphic representation of the World Wide Web around Wikipedia The World Wide Web (WWW or simply the Web) is an information space in which the items of interest, referred to as resources, are identified by global identifiers called Uniform Resource Identifiers (URIs). ...
Jon Bosak led the creation of the XML specification at the W3C. Tim Bray, who was one of the editors of the XML specification, has this to say in his note on Bosak in his annotated version of the spec: Jon Bosak is the single person without whose efforts XML...
1996 (MCMXCVI) is a leap year starting on Monday of the Gregorian calendar, and was designated the International Year for the Eradication of Poverty. ...
Microsoft Corporation (NASDAQ: MSFT, HKEx: 4338) is the worlds largest software company, with 2005 global annual sales of 40 billion US dollars and nearly 60,000 employees in 85 countries and regions. ...
XML was designed by an eleven-member Working Group supported by an (approximately) 150-member Interest Group. Technical debate took place on the Interest Group mailing list and issues were resolved by consensus or, when that failed, majority vote of the Working Group. James Clark served as Technical Lead of the Working Group, notably contributing the empty-element "<empty/>" syntax and the name "XML". Other names that had been put forward for consideration included "MAGMA" (Minimal Architecture for Generalized Markup Applications), "SLIM" (Structured Language for Internet Markup) and "MGML" (Minimal Generalized Markup Language). The co-editors of the specification were originally Tim Bray and Michael Sperberg-McQueen. Halfway through the project Bray accepted a consulting engagement with Netscape, provoking vociferous protests from Microsoft. Bray was temporarily asked to resign the editorship. This led to intense dispute in the Working Group, eventually solved by the appointment of Microsoft's Jean Paoli as a third co-editor. James Clark, (February 23, 1964) is the author of groff and expat and has done much work with open software and XML. Born in London, educated at Charterhouse and Merton College, Oxford, Clark has lived in Bangkok, Thailand since 1995, and now a permanent resident. ...
Timothy William Bray (born 1955), commonly known as Tim Bray, co-invented XML and XML namespaces while an Invited Expert at the World Wide Web Consortium between 1996 and 1999. ...
Netscape Communications Corporation was the publisher of the Netscape Navigator web browser as well as many other internet and intranet client and server software products. ...
The XML Working Group never met face-to-face; the design was accomplished using a combination of email and weekly teleconferences. The major design decisions were reached in twenty weeks of intense work between July and November of 1996. Further design work continued through 1997, and XML 1.0 became a W3C Recommendation on February 10, 1998 . 1997 (MCMXCVII) is a common year starting on Wednesday of the Gregorian calendar. ...
February 10 is the 41st day of the year in the Gregorian Calendar. ...
1998 (MCMXCVIII) is a common year starting on Thursday of the Gregorian calendar, and was designated the International Year of the Ocean. ...
XML 1.0 achieved the Working Group's goals of Internet usability, general-purpose usability, SGML compatibility, facilitation of easy development of processing software, minimization of optional features, legibility, formality, conciseness, and ease of authoring.
Clarifications and minor changes were accumulated in published errata and then incorporated into a Second Edition of the XML 1.0 Recommendation on October 6, 2000. Subsequent errata were incorporated into a Third Edition on February 4, 2004. October 6 is the 279th day of the year (280th in Leap years). ...
This article is about the year 2000. ...
February 4 is the 35th day of the year in the Gregorian Calendar. ...
2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ...
Also published on the same day as XML 1.0 Third Edition was XML 1.1, a variant of XML that encourages more consistency in how characters are represented and relaxes restrictions on names, allowable characters, and end-of-line representations.
Both XML 1.0 Third Edition and XML 1.1 are considered current versions of XML.
Features of XML XML provides a text-based means to describe and apply a tree-based structure to information. At its base level, all information manifests as text, interspersed with markup that indicates the information's separation into a hierarchy of character data, container-like elements, and attributes of those elements. In this respect, it is similar to the LISP programming language's S-expressions, which describe tree structures wherein each node may have its own property list. There is more than one usage of the word markup. ...
Lisp may mean: Lisp programming language Lisp (speech) This is a disambiguation page, a list of pages that otherwise might share the same title. ...
An S-expression (S stands for symbolic) is a convention for representing data or an expression in a computer program in a text form. ...
The fundamental unit in XML is the character, as defined by the Universal Character Set. Characters are combined in certain allowable combinations to form an XML document. The document consists of one or more entities, each of which is typically some portion of the document's characters, encoded as a series of bits and stored in a text file. The international standard ISO/IEC 10646 defines the Universal Character Set (UCS) as a character encoding. ...
In communications, a code is a rule for converting a piece of information (for example, a letter, word, or phrase) into another form or representation, not necessarily of the same sort. ...
This article is about the unit of information. ...
Computer files can be divided into two broad categories: binary and text. ...
The ubiquity of text file authoring software (word processors) facilitates rapid XML document authoring and maintenance, whereas prior to the advent of XML, there were very few data description languages that were general-purpose, Internet protocol-friendly, and very easy to learn and author. In fact, most data interchange formats were proprietary, special-purpose, "binary" formats (based foremost on bit sequences rather than characters) that could not be easily shared by different software applications or across different computing platforms, much less authored and maintained in common text editors. A word processor (also more formally known as a document preparation system) is a computer application used for the production (including composition, editing, formatting, and possibly printing) of any sort of viewable or printed material. ...
By leaving the names, allowable hierarchy, and meanings of the elements and attributes open and definable by a customizable schema, XML provides a syntactic foundation for the creation of custom, XML-based markup languages. The general syntax of such languages is rigid — documents must adhere to the general rules of XML, assuring that all XML-aware software can at least read (parse) and understand the relative arrangement of information within them. The schema merely supplements the syntax rules with a set of constraints. Schemas typically restrict element and attribute names and their allowable containment hierarchies, such as only allowing an element named 'birthday' to contain 1 element named 'month' and 1 element named 'day', each of which has to contain only character data. The constraints in a schema may also include data type assignments that affect how information is processed; for example, the 'month' element's character data may be defined as being a month according to a particular schema language's conventions, perhaps meaning that it must not only be formatted a certain way, but also must not be processed as if it were some other type of data. XML Schema, published as a W3C Recommendation in May 2001, is one of several XML schema languages. ...
On computer science, a datatype (often simply type) is a name or label for a set of values and some operations which can be performed on that set of values. ...
In this way, XML contrasts with HTML, which has an inflexible, single-purpose vocabulary of elements and attributes that, in general, cannot be repurposed. With XML, it is much easier to write software that accesses the document's information, since the data structures are expressed in a formal, relatively simple way.
XML makes no prohibitions on how it is used. Although XML is fundamentally text-based, software quickly emerged to abstract it into other, richer formats, largely through the use of datatype-oriented schemas and object-oriented programming paradigms (in which the document is manipulated as an object). Such software might only treat XML as serialized text when it needs to transmit data over a network, and some software doesn't even do that much. Such uses have led to "binary XML", the relaxed restrictions of XML 1.1, and other proposals that run counter to XML's original spirit and thus garner an amount of criticism. In computer science, abstraction is a mechanism and practice to reduce and factor out details so that one can focus on few concepts at a time. ...
In computer science, object-oriented programming, OOP for short, is a computer programming paradigm. ...
Strengths and weaknesses Some features of XML that make it well-suited for data transfer are: XML is also heavily used as a format for document storage and processing, both online and offline, and offers several benefits: Human-readable refers to a representation of information that can be naturally read by humans. ...
The term machine-readable or computer-readable refers to information encoded in a form which can be read or understood by a machine / computer and interpreted by hardware and / or software. ...
Unicode is an industry standard whose goal is to provide the means by which text of all forms and languages can be encoded for use by computers. ...
Wikibooks Wikiversity has more about this subject: School of Computer Science Open Directory Project: Computer Science Downloadable Science and Computer Science books Collection of Computer Science Bibliographies Belief that title science in computer science is inappropriate Categories: | ...
A binary tree, a simple type of branching linked data structure. ...
This article is about the data structure. ...
In computer science, a list is an abstract concept denoting an ordered collection of fixed-length entities. ...
In computer science, a tree is a widely-used computer data structure that emulates a tree structure with a set of linked nodes. ...
In computer science, self-documenting refers to the ability of a file format to require little or no previous knowledge of that formats specifications. ...
The structure of a thing is how the parts of it relate to each other, how it is put together. This contrast with process, which is how the thing works; but process requires a viable structure. ...
This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ...
Syntax, originating from the Greek words συν (syn, meaning co- or together) and τάξις (táxis, meaning sequence, order, arrangement), can be described as the study of the rules, or patterned relations that govern the way the words in a sentence come together. ...
A parser is a computer program or a component of a program that analyses the grammatical structure of an input, with respect to a given formal grammar, a process known as parsing. ...
- its robust, logically-verifiable format is based on international standards;
- the hierarchical structure is suitable for most (but not all) types of documents;
- it manifests as plain text files, unencumbered by licenses or restrictions;
- it is platform-independent, thus relatively immune to changes in technology;
- it and its predecessor, SGML, have been in use since 1986, so there is extensive experience and software available.
For certain applications, XML also has the following weaknesses: Standards are produced by many organisations, some for internal usage only, others for use by a groups of people, groups of companies, or a subsection of an industry. ...
A hierarchy (in Greek: ΙεÏαÏχία, it is derived from ιεÏός-hieros, sacred, and άÏχω-arkho, rule) is a system of ranking and organizing things or people. ...
Computer files can be divided into two broad categories: binary and text. ...
The Standard Generalized Markup Language (SGML) is a metalanguage in which one can define markup languages for documents. ...
- Its syntax is fairly verbose and partially redundant. This can hurt human readability and application efficiency, and yields higher storage costs. It can also make XML difficult to apply in cases where bandwidth is limited, though compression can reduce the problem in some cases. This is particularly true for multimedia applications running on cell phones and PDAs which want to use XML to describe images and video.
- Parsers should be designed to recurse arbitrarily nested data structures and must perform additional checks to detect improperly formatted or differently ordered syntax or data (this is because the markup is descriptive and partially redundant, as noted above). This causes a significant overhead for most basic uses of XML, particularly where resources may be scarce - for example in embedded systems. Furthermore, additional security considerations arise when XML input is fed from untrustworthy sources, and resource exhaustion or stack overflows are possible.
- Some consider the syntax to contain a number of obscure, unnecessary features born of its legacy of SGML compatibility. However, an effort to settle on a subset called "Minimal XML" led to the discovery that there was no consensus on which features were in fact obscure or unnecessary.
- The basic parsing requirements do not support a very wide array of data types, so interpretation sometimes involves additional work in order to process the desired data from a document. For example, there is no provision in XML for mandating that "3.14159" is a floating-point number rather than a seven-character string. XML schema languages add this functionality.
- Modelling overlapping (non-hierarchical) data structures requires extra effort.
- Mapping XML to the relational or object oriented paradigms is often cumbersome.
- Some have argued that XML can be used as a data storage only if the file is of low volume, but this is only true given particular assumptions about architecture, data, implementation, and other issues.
Bandwidth is a measure of frequency range. ...
There are several types of compression: physical compression data compression multimedia compression image compression executable compression audio compression video compression bandwidth compression audio level compression compression (functional analysis) See also Arch bridge Compression arch suspended-deck bridge Compressor Compression ratio This is a disambiguation page, a list of pages that...
An embedded system is a special-purpose computer system, which is completely encapsulated by the device it controls. ...
The Standard Generalized Markup Language (SGML) is a metalanguage in which one can define markup languages for documents. ...
On computer science, a datatype (often simply type) is a name or label for a set of values and some operations which can be performed on that set of values. ...
XML Schema, published as a W3C Recommendation in May 2001, is one of several XML schema languages. ...
Object-oriented programming (OOP) is a computer programming paradigm in which a software system is modeled as a set of objects that interact with each other. ...
Since the late 1800s, the word paradigm (IPA: ) has referred to a thought pattern in any scientific discipline or other epistemological context. ...
Quick syntax tour Here is an example of a simple recipe expressed using XML: <?xml version="1.0" encoding="UTF-8"?> <Recipe name="bread" prep_time="5 mins" cook_time="3 hours"> <title>Basic bread</title> <ingredient amount="3" unit="cups">Flour</ingredient> <ingredient amount="0.25" unit="ounce">Yeast</ingredient> <ingredient amount="1.5" unit="cups">Warm Water</ingredient> <ingredient amount="1" unit="teaspoon">Salt</ingredient> <Instructions> <step>Mix all ingredients together, and knead thoroughly.</step> <step>Cover with a cloth, and leave for one hour in warm room.</step> <step>Knead again, place in a tin, and then bake in the oven.</step> </Instructions> </Recipe> The first line is the XML declaration: it is an optional line stating what version of XML is in use (normally version 1.0), and may also contain information about character encoding and external dependencies.
The remainder of this document consists of nested elements, some of which have attributes and content. An element typically consists of two tags, a start tag and an end tag, possibly surrounding text and other elements. The start tag consists of a name surrounded by angle brackets, like "<step>"; the end tag consists of the same name surrounded by angle brackets, but with a forward slash preceding the name, like "</step>". The element's content is everything that appears between the start tag and the end tag, including text and other (child) elements. The following is a complete XML element, with start tag, text content, and end tag:
<step>Knead again, place in a tin, and then bake in the oven.</step> In addition to content, an element can contain attributes — name-value pairs included in the start tag after the element name. Attribute values must always be quoted, using single or double quotes, and each attribute name should appear only once in any element. <ingredient amount="3" unit="cups">Flour</ingredient> In this example, the ingredient element has two attributes: amount, having value "3", and units, having value "cups". In both cases, at the markup level, the names and values of the attributes, just like the names and content of the elements, are just textual data — the "3" and "cups" are not a quantity and unit of measure, respectively, but rather are just character sequences that the document author may be using to represent those things.
In addition to text, elements may contain other elements:
<Instructions> <step>Mix all ingredients together, and knead thoroughly.</step> <step>Cover with a cloth, and leave for one hour in warm room.</step> <step>Knead again, place in a tin, and then bake in the oven.</step> </Instructions> In this case, the Instructions element contains three step elements. XML requires that elements be properly nested — elements may never overlap. For example, this is not well-formed XML, because the em and strong elements overlap: <!-- WRONG! NOT WELL-FORMED XML! --> <p>Normal <em>emphasized <strong>strong emphasized</em> strong</strong></p> Every XML document must have exactly one top-level root element (alternatively called a document element), so the following would also be a malformed XML document: <?xml version="1.0" encoding="UTF-8"?> <!-- WRONG! NOT WELL-FORMED XML! --> <thing>Thing one</thing> <thing>Thing two</thing> XML provides special syntax for representing an element with empty content. Instead of writing a start tag followed immediately by an end tag, a document may contain the empty element tag where a slash follows the element name. The following two examples are functionally equivalent: <foo></foo> <foo/> XML provides two methods for escaping (or simply representing) special characters: entity references and numeric character references. An entity in XML is a named body of data, usually representing text, such as an unusual character. An entity reference is a placeholder for that entity, and consists of the entity's name preceded by an ampersand ("&") and followed by a semicolon (";"). XML has several predeclared entities, such as "lt" (referenced as "<") for the left angle bracket (<) and "amp" (referenced as "&") for the ampersand (&) itself, and it is possible to declare additional ones if desired. Aside from representing individual characters, reproducing chunks of boilerplate text is another common use for entities. Here is an example using a predeclared XML entity to escape the ampersand in the name "AT&T": A numeric character reference (NCR) is a common markup construct used in SGML and other SGML-based markup languages such as HTML and XML. It consists of a short sequence of characters that, in turn, represent a single character from the Universal Character Set (UCS) or Unicode. ...
The roman ampersand on the left is stylised, but the italic one on the right is clearly similar to et. An ampersand (&) is a logogram representing the word logical conjunction and. The symbol is a ligature of the letters in et, which is Latin for and. Its origin is apparent...
A semicolon ( ; ) is a type of punctuation mark. ...
<company-name>AT&T</company-name> The full list of predeclared entities are - & (&)
- < (<)
- > (>)
- ' (')
- " (")
If more entities need to be declared, this is done in the document's DTD, which is not demonstrated in this example, for brevity. The Extensible Markup Language (XML) is a W3C-recommended general-purpose markup language for creating special-purpose markup languages, capable of describing many different kinds of data. ...
Numeric character references look like entities, but instead of a name, they contain the "#" character followed by a number between the ampersand and the semicolon. The number (in decimal or hexadecimal) represents a Unicode code point, and is typically used to represent characters that are not easily encodable, such as an Arabic character in a document produced on a European computer. The ampersand in the "AT&T" example could also be escaped like this (decimal 38 is the Unicode value for "&"): The correct title of this article is #. The substitution or omission of a # sign is due to technical restrictions. ...
In mathematics and computer science, hexadecimal, or simply hex, is a numeral system with a radix or base of 16 usually written using the symbols 0–9 and A–F or a–f. ...
<company-name>AT&T</company-name> There are many more rules necessary to be sure of writing well-formed XML documents, such as the exact characters allowed in an XML name, but this quick tour provides the basics necessary to read and understand many XML documents.
Correctness in an XML document For an XML document to be correct, it must be: - Well-formed. A well-formed document conforms to all of XML's syntax rules. For example, if a non-empty element has an opening tag with no closing tag, it is not well-formed. A document that is not well-formed is not considered to be XML; a parser is required to refuse to process it.
- Valid. A valid document has data that conforms to a particular set of user-defined content rules that describe correct data values and locations. For example, if an element in a document is required to contain text that can be interpreted as being an integer numeric value, and it instead has the text "hello", is empty, or has other elements in its content, then the document is not valid.
The integers consist of the positive natural numbers (1, 2, 3, …), their negatives (−1, −2, −3, ...) and the number zero. ...
Well-formed documents An XML document is text, which is a sequence of characters. The specification requires support for Unicode encodings UTF-8 and UTF-16 (UTF-32 is not mandatory). The use of other non-Unicode based encodings, such as ISO-8859, is admitted and is indeed widely used and supported. Unicode is an industry standard whose goal is to provide the means by which text of all forms and languages can be encoded for use by computers. ...
UTF-8 (8-bit Unicode Transformation Format) is a variable-length character encoding for Unicode created by Ken Thompson and Rob Pike. ...
In computing, UTF-16 is a 16-bit Unicode Transformation Format, a character encoding form that provides a way to represent a series of abstract characters from Unicode and ISO/IEC 10646 as a series of 16-bit words suitable for storage or transmission via data networks. ...
UTF-32 is a method of encoding Unicode characters, using a fixed amount of 32 bits for each character. ...
ISO 8859, more formally ISO/IEC 8859, is a joint ISO and IEC standard for 8-bit character encodings for use by computers. ...
A well-formed document must conform to the following rules, among others:
- One and only one root element exists for the document. However, the XML declaration, processing instructions, and comments can precede the root element.
- Non-empty elements are delimited by both a start-tag and an end-tag.
- Empty elements may be marked with an empty-element (self-closing) tag, such as
<IAmEmpty/>. This is equal to <IAmEmpty></IAmEmpty>. - All attribute values are quoted, either single (') or double (") quotes. Single quotes close a single quote and double quotes close a double quote.
- Tags may be nested but may not overlap. Each non-root element must be completely contained in another element.
- The document complies to its character set definition. The charset is usually defined in the xml declaration but it can be provided by the transport protocol, such as HTTP. If no charset is defined, usage of a Unicode encoding is assumed, defined by the Unicode Byte Order Mark. If the mark does not exist, UTF-8 is the default.
Element names are case-sensitive. For example, the following is a well-formed matching pair Each XML document has one, and exactly one single root element. ...
In computing, a protocol is a convention or standard that controls or enables the connection, communication, and data transfer between two computing endpoints. ...
HTTP (for HyperText Transfer Protocol) is the primary method used to convey information on the World Wide Web. ...
Unicode is an industry standard whose goal is to provide the means by which text of all forms and languages can be encoded for use by computers. ...
A Byte Order Mark (BOM) is the character at code point FEFF (ZERO-WIDTH NO-BREAK SPACE), when that character is used to denote the Endianness of a string of UCS/Unicode characters encoded in UTF-16 or UTF-32. ...
UTF-8 (8-bit Unicode Transformation Format) is a variable-length character encoding for Unicode created by Ken Thompson and Rob Pike. ...
<Step> ... </Step> whereas this is not <Step> ... </step> The careful choice of names for XML elements will convey the meaning of the data in the markup. This increases human readability while retaining the rigor needed for software parsing. The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ...
DATA (Debt, AIDS, Trade, Africa) was established in 2002 by Bono (Paul Hewson) of the Rock band U2, and Bobby Shriver, along with activists from the Jubilee 2000 Drop the Debt Campaign, as an organisaton focused on Justice, not charity. ...
Markup refers to the use of a markup language to describe the structure and appearance of a particular document. ...
Choosing meaningful names implies the semantics of elements and attributes to a human reader without reference to external documentation. However, this can lead to verbosity, which complicates authoring and increases file size.
Valid documents An XML document that complies with a particular schema, in addition to being well-formed, is said to be valid. The word schema comes from the Greek word σχήμα (skhēma) that means shape or more generally plan. ...
An XML schema is a description of a type of XML document, typically expressed in terms of constraints on the structure and content of documents of that type, above and beyond the basic constraints imposed by XML itself. A number of standard and proprietary XML schema languages have emerged for the purpose of formally expressing such schemas, and some of these languages are XML-based, themselves. XML Schema, published as a W3C Recommendation in May 2001, is one of several XML schema languages. ...
Before the advent of generalised data description languages such as SGML and XML, software designers had to define special file formats or small languages to share data between programs. This required writing detailed specifications and special-purpose parsers and writers. A file format is a particular way to encode information for storage in a computer file. ...
XML's regular structure and strict parsing rules allow software designers to leave parsing to standard tools, and since XML provides a general, data model-oriented framework for the development of application-specific languages, software designers need only concentrate on the development of rules for their data, at relatively high levels of abstraction. A data model is a model that describes in an abstract way how data is represented in a business organization, an information system or a database management system. ...
Well-tested tools exist to validate an XML document "against" a schema: the tool automatically verifies whether the document conforms to constraints expressed in the schema. Some of these validation tools are included in XML parsers, and some are packaged separately.
Other usages of schemas exist: XML editors, for instance, can use schemas to support the editing process.
DTD The oldest schema format for XML is the Document Type Definition (DTD), inherited from SGML. While DTD support is ubiquitous due to its inclusion in the XML 1.0 standard, it is seen as limited for the following reasons: A Document Type Definition (DTD for short) is a set of declarations that conform to a particular markup syntax and that describe a class, or type, of SGML or XML documents, in terms of constraints on the structure of those documents. ...
- It has no support for newer features of XML, most importantly namespaces.
- It lacks expressivity. Certain formal aspects of an XML document cannot be captured in a DTD.
- It uses a custom non-XML syntax, inherited from SGML, to describe the schema.
XML Schema A newer XML schema language, described by the W3C as the successor of DTDs, is XML Schema, or more informally referred to in terms of the initialism for XML Schema instances, XSD (XML Schema Definition). XSDs are far more powerful than DTDs in describing XML languages. They use a rich datatyping system, allow for more detailed constraints on an XML document's logical structure, and are required to be processed in a more robust validation framework. Additionally, XSDs use an XML based format, which makes it possible to use ordinary XML tools to help process them, although WXS (W3C XML Schema) implementations require much more than just the ability to read XML. XML Schema, published as a W3C Recommendation in May 2001, is one of several XML schema languages. ...
It has been suggested that this article or section be merged with Apocopation. ...
An XML Schema Definition (XSD) is an instance of a W3C XML Schema. ...
In computer science, a datatype (often simply a type) is a name or label for a set of values and some operations which one can perform on that set of values. ...
Criticisms of WXS include the following:
- The specification is very large, which makes it difficult to understand and implement.
- The XML-based syntax leads to verbosity in schema description, which makes XSDs harder to read and write.
RELAX NG Another popular schema language for XML is RELAX NG. Initially specified by OASIS, RELAX NG is now also an ISO international standard (as part of DSDL). It has two formats: an XML based syntax and a non-XML compact syntax. The compact syntax aims to increase readability and writability, but since there is a well-defined way to translate compact syntax to the XML syntax and back again by means of James Clark's Trang conversion tool, the advantage of using standard XML tools is not lost. Compared to XML Schema, RELAX NG has a simpler definition and validation framework, making it easier to use and implement. It also has the ability to use any datatype framework on a plug-in basis; for example, a RELAX NG schema author can require values in an XML document to conform to definitions in XML Schema Datatypes. In computing, RELAX NG (REgular LAnguage for XML Next Generation) is a schema language for XML, based on Murata Makotos RELAX and James Clarks TREX. A RELAX NG schema specifies a pattern for the structure and content of an XML document. ...
The Organization for the Advancement of Structured Information Standards (OASIS) is a global consortium that drives the development, convergence and adoption of e-business and web service standards. ...
Document Schema Definition Languages (DSDL) is a framework within which multiple validation tasks of different types can be applied to an XML document in order to achieve more complete validation results than just the application of a single technology. ...
James Clark, (February 23, 1964) is the author of groff and expat and has done much work with open software and XML. Born in London, educated at Charterhouse and Merton College, Oxford, Clark has lived in Bangkok, Thailand since 1995, and now a permanent resident. ...
Other schema languages Some schema languages not only describe the structure of a particular XML format but also offer limited facilities to influence processing of individual XML files that conform to this format. DTDs and XSDs both have this ability; they can for instance provide attribute defaults. RELAX NG intentionally does not provide these facilities.
International and worldwide use XML fully supports unicode character encodings in element names, attributes and data. Therefore the following is a perfectly well-formed XML document, even though it includes both Chinese and Russian characters: Unicode is an industry standard whose goal is to provide the means by which text of all forms and languages can be encoded for use by computers. ...
<?xml version="1.0" encoding="UTF-8"?> <俄语>Данные</俄语>
Displaying XML on the web Extensible Stylesheet Language (XSL) is a supporting technology that describes how to format or transform the data in an XML document. The document is changed to a format suitable for browser display. The process is similar to applying a CSS to an HTML document for rendering. The eXtensible Stylesheet Language (XSL) is a family of languages which allows one to describe how files encoded in the XML standard are to be formatted or transformed. ...
In computing, Cascading Style Sheets (CSS) is a stylesheet language used to describe the presentation of a document written in a markup language. ...
i am a loser In computing, HyperText Markup Language (HTML) is a markup language designed for the creation of web pages and other information viewable in a browser. ...
Without using CSS or XSL, a generic XML document is rendered as raw XML text by most web browsers. Browsers like Internet Explorer, Mozilla and Mozilla Firefox display it with 'handles' that allow parts of the structure to be expanded or collapsed with mouse-clicks. Web browser shortcuts on an Apple computer A web browser is a software application that enables a user to display and interact with HTML documents hosted by web servers or held in a file system. ...
Microsoft Internet Explorer, abbreviated IE or MSIE, is a proprietary web browser made by Microsoft and currently available as part of Microsoft Windows. ...
Mozilla is a computer term that has had many different uses, though all of them have been related to Netscape Communications Corporation and its related application software. ...
Mozilla Firefox is a free, cross-platform, graphical web browser developed by the Mozilla Corporation and hundreds of volunteers. ...
In order to style the rendering in a browser with CSS, the XML document must include a special reference to the stylesheet:
<?xml-stylesheet type="text/css" href="myStyleSheet.css"?> See the CSS article for an example of this in action. In computing, Cascading Style Sheets (CSS) is a stylesheet language used to describe the presentation of a document written in a markup language. ...
This is different from specifying a stylesheet in HTML, which uses the <link> element.
To specify a client-side XSL Transformation (XSLT), the following processing instruction is required in the XML: XSL transformation processing XSL Transformations, or XSLT, is an XML-based language used for the transformation of XML documents. ...
<?xml-stylesheet type="text/xsl" href="transform.xsl"?> Client-side XSLT is not yet supported in Opera. Opera is a computer application for handling most common internet-related tasks, including: web browsing, sending and receiving messages, managing contacts and online chat. ...
The alternative is conversion of XML into HTML, PDF and other formats on the server. Many such processors exist, and the end-user then need not be aware of what has been going on 'behind the scenes'. The eXtensible Stylesheet Language (XSL) is a family of languages which allows one to describe how files encoded in the XML standard are to be formatted or transformed. ...
See the XSLT article for an example of server-side XSLT in action. XSL transformation processing XSL Transformations, or XSLT, is an XML-based language used for the transformation of XML documents. ...
XML extensions - XPath It is possible to refer to individual components of an XML document using XPath. This allows stylesheets in (for example) XSL and XSLT to dynamically "cherry-pick" pieces of a document in any sequence needed in order to compose the required output.
- XQuery is to XML what SQL is to relational databases.
- XML namespaces enable the same document to contain XML elements and attributes taken from different vocabularies, without any naming collisions occurring.
- XML Signature defines the syntax and processing rules for creating digital signatures on XML content.
- XML Encryption defines the syntax and processing rules for encrypting XML content.
- XPointer is a system for addressing components of XML-based internet media.
XPath (XML Path Language) is a terse (non-XML) syntax for addressing portions of an XML document. ...
The eXtensible Stylesheet Language (XSL) is a family of languages which allows one to describe how files encoded in the XML standard are to be formatted or transformed. ...
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XQuery is a query language (with some programming language features) that is designed to query collections of XML data. ...
Structured Query Language (SQL) is the most popular computer language used to create, modify and query databases. ...
An XML namespace is a W3C standard for providing uniquely named elements and attributes in an XML instance. ...
XML Signature (also called XMLDsig) is a W3C recommendation that defines an XML syntax for digital signatures. ...
In cryptography, digital signatures are a method of authenticating digital information often treated, sometimes too closely, as analogous to a physical signature on paper. ...
XML Encryption is a specification that defines how to encrypt the content of an XML element. ...
In cryptography, encryption is the process of obscuring information to make it unreadable without special knowledge. ...
XPointer is a system for addressing components of XML based internet media. ...
Processing XML files SAX and DOM are APIs widely used to process XML data. SAX is used for serial processing whereas DOM is used for random-access processing. Another form of XML Processing API is data binding, where XML data is made available as a strongly typed programming language data structure, in contrast to the DOM. Example data binding systems are the Java Architecture for XML Binding (JAXB) [1] and the Strathclyde Novel Architecture for Querying XML (SNAQue) [2]. SAX is a serial access parser API for XML. Sax provides a mechanism for reading data from an XML document. ...
Document Object Model (DOM) is a form of representation of structured documents as an object-oriented model. ...
API with 3 clients, using the Unified Modeling Language notation An application programming interface (API) is a set of definitions of the ways one piece of computer software communicates with another. ...
A filter in the Extensible Stylesheet Language (XSL) family can transform an XML file for displaying or printing. The eXtensible Stylesheet Language (XSL) is a family of languages which allows one to describe how files encoded in the XML standard are to be formatted or transformed. ...
- XSL-FO is a declarative, XML-based page layout language. An XSL-FO processor can be used to convert an XSL-FO document into another non-XML format, such as PDF.
- XSLT is a declarative, XML-based document transformation language. An XSLT processor can use an XSLT stylesheet as a guide for the conversion of the data tree represented by one XML document into another tree that can then be serialized as XML, HTML, plain text, or any other format supported by the processor.
- XQuery is a W3C language for querying, constructing and transforming XML data.
- XPath is a path expression language for selecting data within an XML file. XPath is a sublanguage of both XQuery and XSLT.
The native file format of OpenOffice.org and AbiWord is XML. Some parts of Microsoft Office 11 will also be able to edit XML files with a user-supplied schema (but not a DTD), and on June 2, 2005 Microsoft announced that, by late 2006 all the files created by users of its Office suite of software will be formatted with web-centered XML specifications. There are dozens of other XML editors available. XSL Formatting Objects, or XSL-FO, is an XML markup language for document formatting. ...
PDF is an abbreviation with several meanings: Portable Document Format Post-doctoral fellowship Probability density function There also is an electronic design automation company named PDF Solutions. ...
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XQuery is a query language (with some programming language features) that is designed to query collections of XML data. ...
XPath (XML Path Language) is a terse (non-XML) syntax for addressing portions of an XML document. ...
OpenOffice. ...
AbiWord is a free word processing program under the GPL which runs on Linux, Mac OS, Microsoft Windows, ReactOS, SkyOS, and other operating systems. ...
Microsoft Office is a suite of productivity programs created by Microsoft and developed for Microsoft Windows and Apple Macintosh operating systems. ...
2 June is the 153rd day of the year in the Gregorian calendar (154th in leap years), with 212 days remaining. ...
2005 (MMV) is a common year starting on Saturday of the Gregorian calendar. ...
An XML editor is a markup language editor with added functionality to facilitate the editing of XML. This could be done in plain text in a text editor such as Vim, with all the code visible. ...
Versions of XML There are two current versions of XML. The first, XML 1.0, was initially defined in 1998. It has undergone minor revisions since then, without being given a new version number, and is currently in its third edition, as published on February 4, 2004. It is widely implemented and still recommended for general use. The second, XML 1.1, was initially published on the same day as XML 1.0 Third Edition. It contains features — some contentious — that are intended to make XML easier to use for certain classes of users (mainframe programmers, mainly). XML 1.1 is not very widely implemented and is recommended for use only by those who need its unique features. 1998 (MCMXCVIII) is a common year starting on Thursday of the Gregorian calendar, and was designated the International Year of the Ocean. ...
February 4 is the 35th day of the year in the Gregorian Calendar. ...
2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ...
XML 1.0 and XML 1.1 differ in the requirements of characters used for element and attribute names: XML 1.0 only allows characters which are defined in Unicode 2.0, which includes most world scripts, but excludes those which were added in later Unicode versions. Among the excluded scripts are Mongolian, Cambodian, Amharic, Burmese, and others. Unicode is an industry standard whose goal is to provide the means by which text of all forms and languages can be encoded for use by computers. ...
Amharic (አማርኛ) is a Semitic language spoken in Northern Central Ethiopia, where it is the official language. ...
XML 1.1 allows the use of more control characters than XML 1.0. In fact, almost any Unicode character can be used in the character data and attribute values of an XML 1.1 document, even if the character is not defined, aside from having a code point, in the current version of Unicode. In computing, a control character or non-printing character, is a code point (a number) in a character set that does not, in itself, represent a written symbol. ...
Other minor changes between XML 1.0 and XML 1.1 are that control characters are now allowed to be included but only when escaped, and two special Unicode line break characters are included and must be treated as whitespace. In computing, a control character or non-printing character, is a code point (a number) in a character set that does not, in itself, represent a written symbol. ...
XML 1.0 documents are also well-formed XML 1.1 documents, with one exception: XML documents that contain unescaped C1 control characters are now malformed: this is because XML 1.1 requires the C1 control characters to be escaped with numeric character references. The C0 and C1 control code sets define control codes for use in text. ...
There are also discussions on an XML 2.0, although it remains to be seen if such will ever come about. XML-SW (SW for skunk works), written by one of the original developers of XML, contains some proposals for what an XML 2.0 might look like: elimination of DTDs from syntax, integration of namespaces, XML Base and XML Information Set (infoset) into the base standard. A modern Skunk works project leverages an older: LASRE and SR-71 Blackbird. ...
In general, a namespace is an abstract container, which is or could be filled by names, or technical terms, or words, and these represent (stand for) real-world things. ...
This page is a candidate for speedy deletion. ...
XML Information Set (Infoset) is a W3C recommendation. ...
The World Wide Web Consortium also has a XML Binary Characterization Working Group doing preliminary research into use cases and properties for a binary encoding of the XML infoset. The working group is not chartered to produce any official standards. Since XML is by definition text-based, ITU-T and ISO are using the name Fast Infoset for their own binary infoset to avoid confusion (see ITU-T Rec. X.891 | ISO/IEC 24824-1).
Patent status In October 2005 the small company Scientigo publicly asserted that two of its patents, U.S. Patent 5842213 and U.S. Patent 6393426, apply to the use of XML. The patents cover the transfer of "data in neutral forms", according to their applications, which were filed in 1997 and 1999. Scientigo CEO Doyal Bryant expressed a desire to "monetize" the patents but stated that the company was "not interested in having us against the world." He said that Scientigo was discussing the patents with several large corporations.[3] Scientigo is a United States company based Charlotte, North Carolina that began asserting patent claims over XML technology in 2005. ...
XML users and independent experts responded to Scientigo's claims with widespread skepticism and criticism. Some derided the company as a patent troll. Tim Bray described any claims that the patents covered XML as "ridiculous on the face of it"[4]. Because there exists a large amount of prior art relating to XML, some legal experts believed it would be difficult for Scientigo to enforce its patents through litigation. Patent troll (also patent pirate) is a derogatory phrase coined by former Intel assistant general counsel, Peter Detkin, in 2001. ...
In most patent laws, prior art or state of the art is all information that has been disclosed to the public in any form before a given date. ...
Microsoft has also been accused of applying for patents that, if granted, could restrict the use of XML.[5] Microsoft Corporation (NASDAQ: MSFT, HKEx: 4338) is the worlds largest software company, with 2005 global annual sales of 40 billion US dollars and nearly 60,000 employees in 85 countries and regions. ...
Quotes about XML - "XML is a giant step in no direction at all" -- Erik Naggum
- "Some people, when confronted with a problem, think “I know, I’ll use XML.” Now they have two problems." -- dirtsimple.org[6]
See also XML Schema, published as a W3C Recommendation in May 2001, is one of several XML schema languages. ...
A Document Type Definition (DTD for short) is a set of declarations that conform to a particular markup syntax and that describe a class, or type, of SGML or XML documents, in terms of constraints on the structure of those documents. ...
XML Schema, published as a W3C Recommendation in May 2001, is one of several XML schema languages. ...
In computing, RELAX NG (REgular LAnguage for XML Next Generation) is a schema language for XML, based on Murata Makotos RELAX and James Clarks TREX. A RELAX NG schema specifies a pattern for the structure and content of an XML document. ...
Document Schema Definition Languages (DSDL) is a framework within which multiple validation tasks of different types can be applied to an XML document in order to achieve more complete validation results than just the application of a single technology. ...
API with 3 clients, using the Unified Modeling Language notation An application programming interface (API) is a set of definitions of the ways one piece of computer software communicates with another. ...
This article needs to be cleaned up to conform to a higher standard of quality. ...
SAX is a serial access parser API for XML. Sax provides a mechanism for reading data from an XML document. ...
ECMAScript for XML (E4X) is a programming language extension that adds native XML support to ECMAScript (JavaScript). ...
In computing, Cascading Style Sheets (CSS) is a stylesheet language used to describe the presentation of a document written in a markup language. ...
The eXtensible Stylesheet Language (XSL) is a family of languages which allows one to describe how files encoded in the XML standard are to be formatted or transformed. ...
An S-expression (S stands for symbolic) is a convention for representing data or an expression in a computer program in a text form. ...
XQuery is a programming language under development by the W3C thats designed to query collections of XML data. ...
Lloyd smells. ...
XRI (eXtensible Resource Identifier) is a scheme and resolution protocol for abstract identifiers compatible with Uniform Resource Identifiers and Internationalized Resource Identifiers, developed by the XRI Technical Committee at OASIS. The goal of XRIs is to provide a universal format for identifiers that are domain-, location-, application-, and transport-independent...
XDI (XRI Data Interchange) is a generalized, extensible service for sharing, linking, and synchronizing data over the Internet and other data networks using XML documents and XRIs (Extensible Resource Identifiers). ...
The eXtensible Metadata Platform or XMP is a specific type of extensible markup language used in photography and photo editing applications. ...
Scalable Vector Graphics (SVG) is an XML markup language for describing two-dimensional vector graphics, both static and animated. ...
In telecommunications and computer networking abstract syntax notation one (ASN.1) is a standard, flexible method that describes data structures for representing, encoding, transmitting, and decoding data. ...
In an older computer science context serialization means to force one-at-a-time access for the purposes of concurrency control. ...
The following is a list of general purpose markup languages: ASN.1 (Abstract Syntax Notation One) EBML GML - the predecessor of SGML SGML - a predecessor of XML XML See also Comparison of document markup languages Comparison of general purpose markup languages Markup language Simple Declarative Language [1] S-expression Categories...
The following tables compare XML compatibility and support for a number of layout engines. ...
Single source publishing or single sourcing allows the same content to be used in different documents and in various formats. ...
Extensible Binary Meta Language, or EBML, is a generalized file format for (theoretically) any kind of data, aiming to be a binary equivalent to XML. It was originally developed for the Matroska audio/video container format. ...
References Timothy William Bray (born 1955), commonly known as Tim Bray, co-invented XML and XML namespaces while an Invited Expert at the World Wide Web Consortium between 1996 and 1999. ...
The Association for Computing Machinery, or ACM, was founded in 1947 as the worlds first scientific and educational computing society. ...
External links Wikipedia does not have an article with this exact name. ...
Wikibooks logo Wikibooks, previously called Wikimedia Free Textbook Project and Wikimedia-Textbooks, is a sister project to Wikipedia and is part of the Wikimedia foundation, begun on July 10, 2003. ...
Specifications
Basic readings Philip Wadler is a computer scientist well-known for his contributions to programming language design and type theory. ...
Web-Zines
XML editors XSL transformation processing XSL Transformations, or XSLT, is an XML-based language used for the transformation of XML documents. ...
XML certification
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