Schemapath, a minimal extension to xml schema for conditional constraints

In the past few years, a number of constraint languages for XML documents has been proposed. They are cumulatively called schema languages or validation languages and they comprise, among others, DTD, XML Schema, RELAX NG, Schematron, DSD, xlinkit. One major point of discrimination among schema languages is the support of co-constraints, or co-occurrence constraints, e.g., requiring that attribute A is present if and only if attribute B is (or is not) present in the same element. Although there is no way in XML Schema to express these requirements, they are in fact frequently used in many XML document types, usually only expressed in plain human-readable text, and validated by means of special code modules by the relevant applications. In this paper we propose SchemaPath, a light extension of XML Schema to handle conditional constraints on XML documents. Two new constructs have been added to XML Schema: conditions ? based on XPath patterns ? on type assignments for elements and attrib...

• Type: Conference
• Year: 2004
• Where: WWW
• Authors: Claudio Sacerdoti Coen, Paolo Marinelli, Fabio Vitali
• Keywords: Internet Technology, Schema Languages, WWW 2004, XML Document Types, Xml Schema