Business Processes and XML Schema

by Paul Harmon

The Extensible Markup Language (XML) has emerged as the middleware approach of choice for companies that want to create distributed applications (Web services) on the Internet. By itself, XML provides a message format. In the past year, XML has been supplemented by a variety of protocols that extend its power. XML's tag description facility has been extended with XML script to make it easier to describe complex data formats. Simple Object Access Protocol (SOAP) has been widely adopted to provide a transport mechanism. Universal Description, Discovery and Integration (UDDI) and the Web Services Description Language (WSDL) have been adopted as a mechanism for locating potential partners and determining what data formats to use to exchange data with the partners. UDDI defines a repository mechanism, and WSDL provides a script that is used to describe endpoints and possible messages that partners support. E-business XML (ebXML) -- which includes SOAP, UDDI, and WSDL -- is a growing collection of services that will make XML even more useful. For example, ebXML will eventually define security and transaction services.