Editing Schematron (section)

{{short description|Rule-based validation language for XML}}

'''Schematron''' is a rule-based [[XML validation|validation language]] for making assertions about the presence or absence of patterns in [[XML]] trees.  It is a structural schema language expressed in XML using a small number of elements and [[XPath]] languages. In many implementations, Schematron XML is processed into [[XSLT]] code for deployment anywhere that XSLT can be used.

Schematron is capable of expressing constraints in ways that other XML schema languages like [[XML Schema (W3C)|XML Schema]] and [[Document Type Definition|DTD]] cannot. For example, it can require that the content of an element be controlled by one of its siblings. Or it can request or require that the root element, regardless of what element that is, must have specific attributes. Schematron can also specify required relationships between multiple XML files. Constraints and content rules may be associated with "plain-English" (or any language) validation error messages, allowing translation of numeric Schematron error codes into meaningful user error messages. Users of Schematron define all the error messages themselves.<ref>{{Cite book |last=Siegel |first=Erik |title=Schematron: a language for validating XML |date=2022 |publisher=XML Press |isbn=978-1-937434-81-6 |location=Denver, CO}}</ref> 

The current [[International Organization for Standardization|ISO]] recommendation is ''Information technology, Document Schema Definition Languages (DSDL)'', Part 3: ''Rule-based validation, Schematron'' (ISO/IEC 19757-3:2020).