Schema Repositories: What's at Stake? Part II

January 26, 2000

Liora Alschuler

Table of Contents

Part One
The Repositories
Use Cases
What We Really Need

Part Two
Business Schemas
Repositories and Schemas

Sidebar-The Microsoft Effect

The Business of Business Schemas

With a proven framework and set of interoperable vertical schemas, exchange communities could use a repository in real time. Both repository initiatives (BizTalk and are associated with efforts to create frameworks for interoperable business schemas. The BizTalk repository is actually ancillary to the BizTalk Framework Independent Document Specification. OASIS, parent to, is co-sponsor of ebXML together with UN/CEFACT. Let's take a look at what is proposed:


BizTalk Framework



Microsoft Corp.

Sponsor organizations: OASIS, UN/CEFACT


Membership not published, but partial list of 29 organizations, including OAG, the DoD, CommerceOne, and RosettaNet, supplied on request.

Invited and confirmed participants listed on site include over a hundred individuals and organizations, including several major standards organizations as well as vendors and users.


Version 1.0 issued 11/30/99; Version 2.0 available to advisory committee.

First meeting held November 1999; task forces formed; next meeting January 31, 2000; 18 month time-frame projected.


Microsoft specification

Submissions accepted from CEN, UN/CEFACT, CommerceOne, and other organizations


to build "...a set of guidelines for how to publish schemas in XML and how to use XML messages to easily integrate software programs together in order to build rich new solutions."

" leverage what you have today—your existing data models, solutions, and application infrastructure—and adapt it for electronic commerce through the use of XML." (

"to research and identify the technical basis upon which the global implementation of XML can be standardized."

A project "... for the exchange of electronic business data in application-to-application, application-to-person and person-to-application environments." (

The BizTalk Framework describes the schema for BizTalk Messages. The messages start with a transport-specific envelope, which encloses a BizTalk Document. The BizTalk Document header has delivery and manifest information and the body is the actual business document payload. The 1.0 specification addresses logical and physical addressing and point-to-point request/reply exchanges. Subsequent releases will address distribution lists, handlers, anonymous messaging, and publish/subscribe scenarios. The specification complies with the requirements of the BizTalk Server, which can route and manage the messages.

Figure 1: The BizTalk Message Structure, the BizTalk Framework 1.0 Independent Document Specification, November 15, 1999, p.10.

The BizTalk Message Structure

ebXML is a joint project of the United Nations body for Trade Facilitation and Electronic Business (UN/CEFACT) and OASIS, created to "develop a technical framework that will enable XML to be utilized in a consistent manner for the exchange of all electronic business data." Over 150 people participated in the first meeting, including the key players in international EDI.

UN/CEFACT and OASIS characterize ebXML as an 18-month initiative—an ambitious timeframe, even in web time. But a working draft is achievable in that time if they get rapid consensus to incorporate existing work. The semantic layer will come from EDI and EDIFACT, and the XML framework from what is essentially the third generation of CommerceOne's Common Business Language, part of the CommerceNet eCo Framework.

The eCo Framework, which effectively sets the scope of ebXML, is a combination of layered protocols and services that rule the exchange of business information within communities and markets. At XML '99, Dr. Robert J. Glushko, Director of Advanced Technology at Commerce One, Inc, said that the eCo Framework doesn't compete with the other business dialects like OBI and RosettaNet or even BizTalk. Instead, "It creates a world in which they can co-exist and makes it easier to compare and contrast them." It wraps them in a conceptual marketplace.

In this view of the world, the BizTalk specifications could provide an alternate component of messaging semantics, a uniform wrapper for the business documents containing actual business information. In this sense, it would be comparable to the current eCo Framework semantic recommendation (which is derived from legacy EDI systems).

How the eCo Framework Wraps Other E-Commerce Systems

Figure 2: How the eCo Framework Wraps Other E-Commerce Systems; one view of the future of ebXML, from Dr. Robert Glushko, "How XML Enables Internet Trading Communities and Marketplaces," slide 60.

Robert Worden took on the assumptions behind the BizTalk repository/schema scenario in his article, XML E-Business Standards: Promises and Pitfalls, published here on, when he wrote:

"None of the XML repositories will solve the N-squared translation problem for all businesses, unless it can establish a common model of all business information, agreed between all parties, which can then act as an interlingua for all XML translations. The chances of such a massive information model being developed consistently and completely, agreed across all countries and industry sectors, and then maintained effectively, are remote."

Regarding the "supra-standards," such as the eCo Framework, he says that they may manage the complexity of certain dialects, but it is too early to tell which will work and which will flop. Without a universal schema or schema management system anywhere on the horizon, he concludes that organizations should buckle down to the tough but necessary work of building their own gold standard schema since they are going to need it anyway.

My own experience in building interoperable schemas for health care leads me to be somewhat more optimistic on the prospects for some industry-wide or protocol-specific agreements within a reasonable timeframe (say, within 2001) in domains where the EDI legacy has created a basis for shared semantics. I endorse Worden's advice to develop one's own model, and would like to extend it to say that modeling should be done in concert with an industry model or framework, where one exists. Entities can build their own model while they contribute to and extend the common models such as the Health Level 7 (HL7) Reference Information Model (RIM).

At the end of the day, however, you can't magically build a common infrastructure by fiat, regardless of market position or funding or degree of openness. HL7 has been working on the RIM for three years, and it builds on top of a decade of messaging; most verticals are not so far along. So, if unified frameworks are not imminent, where does that leave the repository business?

A Unified Theory of Repositories and Schemas

BizTalk is "ahead" of in the sense that it has actual schemas, but it still functions as a limited catalog-type resource. The wider, shallower net of links cast by's catalog is as useful as BizTalk if you want to know who is doing what and where. While Microsoft can claim an early lead in the repository race, it hardly appears commanding, and significant doubts remain whether anyone is even watching the race.

Users polled at XML'99 either said that they were indifferent or would post on both sites. The search and retrieval aspects of both sites and the basic services offered will have to go through major revisions before either site becomes more than a curiosity for this group. Andrew Hinchley, a consultant working on health care standards architecture for CEN, ISO, and the NHS felt that the proposed schema frameworks, while urgently needed, are either woefully immature or susceptible to the consensual mire of the open standards process. The public draft of the BizTalk schemas require Dun & Bradstreet identifiers (for example), hardly feasible for (say) an English public hospital. At the same time, even eighteen months seems too long to wait for ebXML.

On the other side of the fence, some vendors are adding "now available on" to their PR notices, as if that were a significant mark of industry acceptance. Another vendor claims standards-compliance on the basis of BizTalk tags. On a calmer note, at least one standards-writing organization (which has been courted warmly by both groups) will post to both sites with the caveat that it can be done using an industry-standard schema language. In other words, it will send DTDs today, and later W3C schemas to, but won't translate its specifications to Microsoft's XDR and won't post on until it accepts them in industry-standard markup.

To be useful as a reference catalog, repositories need qualitative analysis. To be useful as a real-time source of interoperable specifications, they need to serve components of a known framework. Until one or both of these criteria are met, repositories can provide a yellow pages directory of schema development, but not much more.

So if the real payback for repositories is either out-of-line with the current repository punchlist or way over the horizon, why have eight companies put up a total of half a million dollars to build one that will stand opposite Microsoft's BizTalk? Why are they focusing on the pot of gold at the end of the rainbow and ignoring the potholes in front of us?

To understand Microsoft's commitment, look at the third leg on the BizTalk stool: first is the repository, second is the schema framework, and third is the BizTalk commercial server. You can't blame Microsoft for using their influence to promote cross-industry support for their product format—anyone would. But when the booster is the big company in Redmond, promotion takes on a different character. (See sidebar: "The Microsoft Effect.")

We cannot forget that the background to the repository competition is the multi-track race to be the authoritative provider of schemas in every domain, from medicine to matchmaking. Schemas and schema frameworks represent the information model on which business is based. Selection and distribution of them is too critical a task to leave to anything less than a vetted source.