Tutorials on Schematron. Introduction Schematron is an XML-based language for validating XML instance documents. Schematron is used to make assertions about data in an XML document. Schematron is used to express operational and business rules. Schematron is an ISO standard. Use Schematron to verify data interdependencies (co-constraints), check data cardinality, and perform algorithmic checks. Schematron. Hibernate can meet your validation needs.