World Wide Web Consortium Issues XML Schema as a Candidate Recommendation

Author(s) and publish date


Implementation testing the key to Interoperability

Testimonials -- 24 October 2000 -- The World Wide Web Consortium (W3C) has issued XML Schema as a W3C Candidate Recommendation. Advancement of the document to Candidate Recommendation is an invitation to the Web development community at large to make implementations of XML Schema and provide technical feedback.

XML Schema Accelerates the XML Revolution

Simply defined, XML Schemas define shared markup vocabularies and allow machines to carry out rules made by people. They provide a means for defining the structure, content and semantics of XML documents.

"Databases, ERP and EDI systems all know the difference between a date and a string of text, but before today, there was no standard way to teach your XML systems the difference. Now there is," declared Dave Hollander, co-chair of the W3C XML Schema Working Group and CTO of Contivo, Inc. "W3C XML Schemas bring to XML the rich data descriptions that are common to other business systems but were missing from XML. Now, developers of XML ecommerce systems can test XML Schema's ability to define XML applications that are far more sophisticated in how they describe, create, manage and validate the information that fuels B2B ecommerce."

The XML Schema specification consists of three parts. One part defines a set of simple datatypes, which can be associated with XML element types and attributes; this allows XML software to do a better job of managing dates, numbers, and other special forms of information. The second part of the specification proposes methods for describing the structure and constraining the contents of XML documents, and defines the rules governing schema-validation of documents. The third part is a primer, which explains what schemas are, how they differ from DTDs, and how someone builds a schema.

By bringing datatypes to XML, XML Schema increases XML's power and utility to the developers of electronic commerce systems, database authors and anyone interested in using and manipulating large volumes of data on the Web. By providing better integration with XML Namespaces, it makes it easier than it has ever been to define the elements and attributes in a namespace, and to validate documents which use multiple namespaces defined by different schemas.

XML Schema Introduces Flexibility, Data Fidelity for Users

XML Schema introduces new levels of flexibility that may accelerate the adoption of XML for significant industrial use. For example, a schema author can build a schema that borrows from a previous schema, but overrides it where new unique features are needed. This principle, called inheritance, is similar to the behavior of Cascading Style Sheets, and allows the user to develop XML Schemas that best suit their needs, without buidling an entirely new vocabulary from scratch.

XML Schema allows the author to determine which parts of a document may be validated, or identify parts of a document where a schema may apply. XML Schema also provides a way for users of ecommerce systems to choose which XML Schema they use to validate elements in a given namespace, thus providing better assurance in ecommerce transactions and greater security against unauthorized changes to validation rules.

Further, as XML Schema are XML documents themselves, they may be managed by XML authoring tools, or through XSLT.

XML Schema is Ready for Implementors

Candidate Recommendation is W3C's public call for implementation, an explicit invitation for W3C members and the developer community at large to review the XML Schema specification and build their own XML Schemas. This period of implementations and reporting allows the editors to learn how developers outside of the Working Group might use them, and where there may be ambiguities for implementors. Public testing and implementation contribute to a more robust XML Schema, and to more widespread use.

XML Schema Has Broad Support

The working group roster reads as a who's who of information technology leaders in research and industry. The members include: Academia Sinica; ArborText, Inc; Bootstrap Alliance and LSU; Calico Commerce; Commerce One; Defense Information Systems Agency (DISA); DevelopMentor; Distributed Systems Technology Centre (DSTC Pty Ltd); Graphic Communications Association; Health Level Seven; Hewlett Packard Company; IBM; Informix; Intel; Lawrence Berkeley National Laboratory; Lexica LLC; Lotus Development Corporation; Microsoft Corporation; Microstar; MITRE; NCR; Oracle Corp.; Progress Software; SAP AG; Software AG; Sun Microsystems; TIBCO Software; University of Edinburgh; webMethods, Inc; Xerox; and XMLSolutions.

Many are committed to current and future product support for XML Schema as it progresses to W3C Recommendation.

About the World Wide Web Consortium [W3C]

The W3C was created to lead the Web to its full potential by developing common protocols that promote its evolution and ensure its interoperability. It is an international industry consortium jointly run by the MIT Laboratory for Computer Science (MIT LCS) in the USA, the National Institute for Research in Computer Science and Control (INRIA) in France and Keio University in Japan. Services provided by the Consortium include: a repository of information about the World Wide Web for developers and users, and various prototype and sample applications to demonstrate use of new technology. To date, over 460 organizations are Members of the Consortium. For more information see


Contact America and Europe --
Janet Daly, <>, +1.617.253.5884 or +1.617.253.2613
Contact Asia --
Kazuhiro Kitagawa <>, +81.466.49.1170

Testimonials for XML Schema Candidate Recommendation

Calico Commerce | Commerce One | Contivo, Inc. | Health Level Seven | IBM | Lotus Development Corporation | Microsoft Corporation | Oracle | Progress Software | SAP | Software AG | TIBCO Software, Inc. | University of Edinburgh |webMethods, Inc.


The promise of the Internet is very much tied to interoperability. And the value proposition of e-business depends on the ability to truly collaborate with partners and customers in a meaningful and efficient way. This emerging XML Schema specification is a key enabler in turning these visions into reality. By establishing standards for managing XML data, W3C is meeting its mission of maximizing the potential of the Web. We at Calico Commerce are also dedicated to this mission, and we are committed to working with other industry leaders to make software more robust and systems more able to change and adapt to evolving situations. In this day when multi-vendor IT environments are the norm in most enterprises, it is critical that we continually find ways to speed application integration and improve data exchange between disparate platforms. It is for this reason that we're incorporating the XML Schema specification into the Calico eBusiness application suite."

-- Mary Holstege, Distinguished Engineer, Calico Commerce


Commerce One recognized in 1997 that the next generation of XML-based applications cannot be built on the same old DTD technology. DTDs are insufficient to support the features required for B2B e-commerce. Since then, Commerce One has been the thought leader in XML schema development through its "Schema for Object-Oriented XML" (SOX). This introduced and implemented ideas such as inheritance, polymorphism, local scoping, a modern modularity mechanism, user-defined datatypes, attribute and model groups, and a multi-level architecture, among others, that are found in this Candidate Recommendation.

Commerce One is pleased to see the development of XML Schema move to the Candidate Recommendation phase and calls on the community to make this phase successful by providing implementation feedback to the Working Group. This will ensure a final Recommendation that truly addresses the community's needs and provides a solid foundation for electronic commerce in the 21st Century. We congratulate the Working Group on achieving this important milestone.

-- Dr. Matthew Fuchs, Senior Architect, Commerce One


Databases, ERP and EDI systems all know the difference between a date and a string of text, but before today, there was no standard way to teach your XML systems the difference. Now there is. Released today, W3C XML Schemas bring to XML the rich data descriptions that are common to other business systems but were missing from XML.

W3C XML Schemas have a strong data type system and improved information modeling features. Now, developers of XML eCommerce Systems can create standard XML applications that are far more sophisticated in how they describe, create, manage and validate the information that fuels B2B eCommerce.

-- Dave Hollander, CTO Contivo, Inc.


Health Level Seven (HL7) congratulates the W3C XML Schema WG on the advancement of the W3C XML Schema specification to Candidate Recommendation status. The XML Schema language will give HL7 a vendor neutral way to more accurately express the constraints of our models in our XML serializations than is currently possible with DTDs. In particular, the addition of datatypes, inheritance in the type system and locally-scoped element declarations are seen as concrete improvements in expressiveness over DTDs. The near-term stability offered by Candidate Recommendation will allow HL7 to begin actively developing the next version of our own standards based on the XML Schema Language.

-- Wesley Rishel, Vice Chair of the Technical Steering Committee, Health Level Seven<


IBM applauds the W3C on this significant step forward, and notes the critical role of XML Schema in the continuing evolution of XML as the preferred vehicle for e-business applications. IBM is committed to open standards and has been involved with XML Schema from the beginning, both in terms of the development of the specification and implementations that have tracked the emerging standard.

-- Robert Sutor, Director of e-business Standards Strategy, IBM


XML Schemas supply the missing link for applying XML to a broad range of industrial strength e-business, collaborative and database applications. Lotus Development is pleased to have contributed to the development of the W3C XML Schemas Candidate Recommendation, and we congratulate the W3C on reaching this important milestone."

-- Nick Shelness, Chief Technology Officer, Lotus Development Corporation


XML Schemas will enable new levels of distributed functionality and interoperability among software products and computer services, and so we are greatly pleased by the advancement of the XML Schema specification to Candidate Recommendation. As one of the original proponents of this work, we have been active contributors to its development and are working to integrate XML Schema in our products. In addition to adding support to our XML parser, XML Schemas are at the foundation of the Microsoft .NET Framework and play an integral role in Visual Studio.Net.

-- Dave Reed, General Manager, Data Access and XML Technologies, Microsoft Corporation


The XML Schema Candidate Recommendation Release is a major milestone towards the overall adoption of XML, and we are very excited to announce its support as part of the Oracle XML Developers Kit. XML Schema is essential to B-to-B integration allowing information to be automatically and instantly exchanged among trading partners."

-- Jeremy Burton, Senior Vice President, Product and Services Marketing, Oracle Corporation


Progress Software is proud to have participated in the development of the XML Schema specification and its progressing to Candidate Recommendation. By standardizing the way in which the meaning, usage and relationships of XML constituent parts are defined, XML Schemas allow Progress to create a robust infrastructure for B2B. Combining the reliable, scalable and secure transport of business-critical data via the SonicMQ Messaging Server, with the XML Schema Mapping facility in Progress 9.1B, will enable the integration of the more than 5,000 Progress-based business applications, with each other as well as with non-Progress applications.

-- Pete Sliwkowski, Vice-President, Progress Software


SAP is pleased to see that XML Schema has become Candidate Recommendation. XML Schema will play an important role in enabling collaborative business scenarios among different application components. SAP is committed to embracing XML Schema throughout its e-business platform,, and to supporting this critical technology to be widely adopted.

-- Dr. Peter Barth, Director Corporate Marketing mySAP Technology and mySAP Workplace, SAP AG


Software AG believes that the W3C XML Schema Specification will be central to many software systems. the Candidate Recommendation phase is vital to provide real implementation experience, receive user feedback, and produce a formal model that provides a firm foundation for future work such as the W3C XML Query algebra. We believe this phase is essential to ensure that XML Schema is understandable and implementable, and that implementations that follow the specification are interoperable.

-- Jonathan Robie, R&D Fellow, Software AG


As a leading provider of XML schema solutions, TIBCO Extensibility enthusiastically and fully supports the Candidate Recommendation of the XML Schema Standard from the W3C. As a sign of our commitment we are currently integrating the candidate recommendation into the upcoming releases of our products, including the industry leading Turbo XML(tm) and our enterprise class solution XML Canon(tm). By agreeing upon a comprehensive worldwide schema standard, the W3C has provided the Internet its semantic foundation. By adopting XML Schema, business relationships can now be articulated, integrated, and automated via the Internet with unprecedented speed.

-- Leonard Buck - Chief Scientist and Vice President XML Technologies, TIBCO Software Inc.


We welcome the advance of the XML Schema W3C Working Drafts to Candidate Recommendation status. This event is important not only because of the practical benefits it will bring to the World Wide Web, but also because it represents a major success for collaboration between science and industry: The design of XML Schema depends on a not only on the practical experience of industry, but also on a unique confluence of scientific inputs, from disciplines as diverse as formal language theory, computational linguistics and type theory. We are pleased to have contributed to this work, and are committed to continuing to support it.

-- Henry S. Thompson, Reader in Artificial Intelligence and Cognitive Science,University of Edinburgh


webMethods continues to introduce open, innovative solutions that allow companies to overcome traditional B2Bi challenges and quickly create integrated trading networks. We are proud to have been an active member of the XML Schema Working Group and to have delivered support for the April draft. Our webMethods B2Bi Solution Suite will continue to track this emerging standard as we believe the W3C XML Schema will play a major role in streamlining the process of transacting business over the Internet by making the exchange of information between trading partners simpler and more interoperable.

-- Jim Green, CTO and Executive Vice President of Product Development, webMethods, Inc.

Related RSS feed