Editing XML Schema (W3C) (section)

{{Short description|XML standard to describe elements in document}}
{{redirect-distinguish|XSD|XSD (airport)}}
{{infobox file format
| name = XML Schema (W3C)
| extension = .xsd
| mime = application/xml, text/xml
| owner = [[World Wide Web Consortium]]
| genre = [[XML schema#XML schema languages|XML Schema language]]
| extendedfrom = [[XML]]
| standard = [http://www.w3.org/TR/xmlschema-1/ 1.0, Part 1 Structures (Recommendation)],<br/>
[http://www.w3.org/TR/xmlschema-2/ 1.0, Part 2 Datatypes (Recommendation)],<br/>
[http://www.w3.org/TR/xmlschema11-1/ 1.1, Part 1 Structures (Recommendation)],<br/>
[http://www.w3.org/TR/xmlschema11-2/ 1.1, Part 2 Datatypes (Recommendation)]
}}
'''XSD''' ('''XML Schema Definition'''), a recommendation of the World Wide Web Consortium ([[W3C]]), specifies how to formally describe the elements in an Extensible Markup Language ([[XML]]) document. It can be used by programmers to verify each piece of item content in a document, to assure it adheres to the description of the element it is placed in.<ref>"[http://searchsoa.techtarget.com/definition/XSD Definition XSD (XML Schema Definition)]" TechTarget, retrieved 10 June 2014</ref>

Like all [[XML schema|XML schema languages]], XSD can be used to express a set of rules to which an XML document must conform 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 type]]s. Such a post-validation ''[[XML Information Set|infoset]]'' can be useful in the development of XML document processing software. <!-- However, the schema language's dependence on specific data types has provoked criticism.--as documented in the PSVI section below, but links no longer work to understand nature of criticism. -->