Overview#XML schema typically refers to the description or Schema 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.
XML schema, more formally is XML Schema Definition Language (XSD) specifies the XML Schema Definition Language, which offers facilities for describing the structure and constraining the contents of XML documents, including those which exploit the XML Namespace facility.
The schema language, which is itself represented in an XML vocabulary and uses namespaces, substantially reconstructs and considerably extends the capabilities found in XML document type definitions (DTDs).
More Information#There might be more information for this subject on one of the following:
- [#1] - XML_schema - based on information obtained 2018-01-08-
- [#2] - W3C XML Schema Definition Language (XSD) 1.1 Part 1: Structures - based on information obtained 2018-01-08-