Visual modeling of XML constraints based on a new extensible constraint markup language

The eXtensible Markup Language (XML) is rapidly becoming the industry standard format for exchanging information across the networks. The validity of XML documents is very important for users and/or applications that consume them. While Document Type Definition (DTD) and XML Schema can be used to specify and validate the syntax of XML documents, they cannot specify or validate "semantic" constraints such as dynamic value constraints and inter-relationship constraints among element or attribute's values/presence. We propose a new NAIL constraint language - eXtensible Constraint Markup Language (XCML) for specifying XML semantic constraints that are either assertion-based or rule-based. It is much more expressive than the existing XML constraint languages by supporting both dynamic constraints and inter-relationship constraints. We also propose a visual modeling framework of XCML constraints using Object Constraint Language (OCL) of Unified Modeling Language (UML), which automates the generation of XCML and XML Schema instance documents. The framework has been implemented with reusable XSLT stylesheets. The generated XML Schema document is used for syntactic validation. The generated XCML document is further transformed to an XSLT stylesheet by a reusable stylesheet. The transformed stylesheet is then used for semantic validation. The technologies demonstrated here can be used in XML data management, data warehousing, and decision support systems for various industry domains including healthcare information technology and E-Commerce.