Matt Fuchs (Commerce One): Extending XML Schema for eCommerce

Matt Fuchs (Commerce One) is a member of the W3C XML Schema Working Group and one of the authors of the SOX (Schema for Object-Oriented XML) W3C Note, which had a definite influence on the current XML Schema specification. Since business documents often must be processed in different ways by different recipients, Fuchs' main premise was that there must be a way to handle polymorphism if we are to effectively use XML Schema for eCommerce.

Polymorphism is the object-oriented programming concept that, amongst other things, allows a data type or class to be extended to contain new elements and behavior while retaining the elements and behavior of the base data type or class. While SOX and the SOX Bean programming model support polymorphism, the real benefits are extensibility and the ability to process elements that are extensions of base classes as if they were actual instances of the base class. For example, if you extend OrderHeader to CovisintOrderHeader, you can still process CovisintOrderHeader as if it was just OrderHeader without any changes to existing code.

In the abstract to his talk, The Role of an Extensible, Polymorphic Schema Language for Electronic Commerce Communities, Fuchs wrote:

For large scale electronic communities, such as global marketplaces, doing business using XML will require the deployment of schema languages with modern language features, such as object-oriented extensibility, powerful composition features, strong datatyping, and polymorphism. This paper describes how these features, particularly polymorphism, are being used to support trading communities in the Commerce One Global Trading Web. We also demonstrate the complexity of deploying the same functionality through more "traditional" techniques, such as those used by XHTML. While Commerce One's SOX (Schema for Object-Oriented XML) [see also About SOX] was the first publicly available schema language and parser to support all these features, many of them are being adopted by XSDL [XML Schema Definition Language].

Note that SOX is the schema underlying xCBL, Commerce One's Common Business Library, which is one of the business vocabularies that has been considered in the creation of the ebXML core components.

For related XML Schema extensions work, see the article XML 2000 Focuses on Schemas by Eric van der Vlist for XML.com. In particular, note Lee Buck's presentation on Schema Adjunct Framework (SAF) from TIBCO Extensbility, the makers of Turbo XML (XML Authority, XML Instance, and XML Console). Schema Adjunct Framework, intended to become an open standard, is an initiative to define a common vocabulary to extend W3C XML Schema for different purposes, such as database mappings or business rules validation.

Thanks to Brian Hayes and Arofan Gregory of Commerce One for some clarifications to this page.

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