⊿ Point. {R} Glossary. ◢ Keyword: X. ▰ Sources. 〓 Books [B] ◥ University. {q} PhD. ⏫ THEMES. ⏫ Big Data. [B] Big Data. ⚫ USA. ↂ EndNote. ☝️ BD Dummies. XML. Markup language by the W3C for encoding of data Extensible Markup Language (XML) is a markup language and file format for storing, transmitting, and reconstructing arbitrary data. It defines a set of rules for encoding documents in a format that is both human-readable and machine-readable.
The World Wide Web Consortium's XML 1.0 Specification[2] of 1998[3] and several other related specifications[4]—all of them free open standards—define XML.[5] The design goals of XML emphasize simplicity, generality, and usability across the Internet.[6] It is a textual data format with strong support via Unicode for different human languages. Several schema systems exist to aid in the definition of XML-based languages, while programmers have developed many application programming interfaces (APIs) to aid the processing of XML data. Overview[edit] The main purpose of XML is serialization, i.e. storing, transmitting, and reconstructing arbitrary data. Applications[edit] Key terminology[edit] Character Tag <? XML Schema (W3C) Like all XML schema languages, XSD can be used to express a set of rules to which an XML document must conform in order to be considered "valid" according to that schema.
However, unlike most other schema languages, XSD was also designed with the intent that determination of a document's validity would produce a collection of information adhering to specific data types. Such a post-validation infoset can be useful in the development of XML document processing software. The most obvious features offered in XSD that are not available in XML's native Document Type Definitions (DTDs) are namespace awareness and datatypes, that is, the ability to define element and attribute content as containing values such as integers and dates rather than arbitrary text.
The XSD 1.0 specification was originally published in 2001, with a second edition following in 2004 to correct large numbers of errors. XSD 1.1 became a W3C Recommendation in April 2012. The main components of a schema are: General problems: XML Schema. Description of a type of XML document 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 syntactical constraints imposed by XML itself.
These constraints are generally expressed using some combination of grammatical rules governing the order of elements, Boolean predicates that the content must satisfy, data types governing the content of elements and attributes, and more specialized rules such as uniqueness and referential integrity constraints. The mechanism for associating an XML document with a schema varies according to the schema language. The association may be achieved via markup within the XML document itself, or via some external means. Validation[edit] The process of checking to see if a XML document conforms to a schema is called validation, which is separate from XML's core concept of syntactic well-formedness.
Languages[edit] Tool support[edit]