Sticking with XML: Tying Disparate Systems Together

In a forest products company in Washington state, a newly designed e-commerce site allows businesses to order pulp and paper products directly over the Web. Businesses order newsprint and other goods on the site to the tune of nearly $100,000 a day. The orders are collected on a database at the Web site and then carefully transferred to the company’s existing back office system.

But what happens if the person in that all important swivel chair accidentally drops an order or two while transferring information from the new electronic commerce system to the legacy systems that supports the company? Whether it’s information exchanged between partners or simply the transfer of data between newly Internet-enabled applications and older applications, something has to act as the glue between the two.

That glue is turning out to be XML.

The End of HTML

To understand how business-to-business e-commerce has been transformed by XML, it’s important to understand why its ubiquitous predecessor, HTML, wasn’t up to the task.

HTML is one of the engines that has driven the electronic commerce revolution. Despite this, even its inventors recognized its limitations. HTML is, effectively, a presentation tool that tells a browser how to arrange text, graphics, and links on a screen. One of the most important things missing is a mechanism for describing the data being presented.

As a result, there is no way to effectively gather data from a Web page. An incredibly patient person might cut and paste the contents of a screenful of information, but no normal person would do it on a regular basis. Suppose you asked to see a list of books on e-commerce from, ordered from cheapest to most expensive. Taking that same data and resorting by the length of the book requires an entirely new interaction between the server and the browser -- generating the exact same query with one minor modification.

One solution is to give the client more information about the data by adding tags. HTML has tags like <B> and <P> to indicate how a browser should display the content of a page. Why not add tags like <AUTHOR>, <PRICE>, or <PAGECOUNT> to let the browser recognize the data contained in the page? This strategy would allow the browser to recognize the data components of the document and make it possible to manipulate or export that data as requested by the user. Unfortunately, adding tags to HTML was one of the most difficult and time-consuming tasks facing Web standards organizations in the 1990s.

Linking Data and Documents

Instead of adding complexity to HTML, the World Wide Web Consortium (W3C, went back to its roots. HTML is based on Standard Generalized Markup Language (SGML), a complex system for describing other languages. Incredibly powerful, SGML has far too much overhead for use on the Internet. Something was needed with the flexibility of SGML, but with the lightweight features of HTML. In February 1998, the W3C produced XML.

While XML can be used to format documents in the same way that HTML does, its true power is in information exchange. XML can support structured documents that contain a view of data, such as the result of a query, a request to download a section of a database, or a dictionary entry describing information available from a Web server.

XML provides a standard, vendor-neutral way for both data and accompanying metadata to move over a network. This makes it possible for two companies to exchange information without having to understand anything about the underlying databases or information sources. To communicate, a source system simply reformats its proprietary information as an XML-compliant document. The system sends that document to any other system or application that can understand XML.

The Tie that Binds

"It’s very clear that XML will be the lingua franca for business-to-business electronic commerce," says Zack Urlocker, vice president of marketing at Active Software Inc. (, a developer of middleware that lets legacy applications work with newer business-to-business e-commerce solutions. "Today, customers expect all applications to work together in real-time -- yet older applications need ways to become a part of an integrated electronic commerce solution. A customer or business partner doesn’t care that one part of the application is built out of e-commerce tools and another uses SAP. They just want it all to work – now! XML is going to be an enabling tool that allows us to make the new generation of e-commerce applications and our older, line-of-business applications seem like one system."

In business-to-business electronic commerce systems, organizations can move data between companies without having to invent custom, special-purpose applications at both ends. There is also no need to invent new mechanisms to move the data around: most data will travel between companies using HTTP and message queuing technologies such as Microsoft Corp.’s ( Message Queue Server and IBM Corp.’s ( MQSeries can also be used.

That’s an important benefit, says Dave Turner, XML product manager at Microsoft. "XML provides a robust infrastructure for formatting data with formal definitions. That means two companies can exchange information in an application-neutral way. Each can use whatever tools they want. Thus, an organization only needs to worry about one mapping to XML (see figure 1)."

Another important benefit is in the integration of e-commerce systems and existing back office systems. Older applications often have no way of understanding XML. If legacy systems can be modified to accept and publish XML documents, or alternatively use middleware for that task, they can suddenly be a part of an integrated business-to-business e-commerce strategy.

Some organizations are using XML to define business processes. According to Versant Corp.’s ( vice president of engineering, Nipun Sehgal, "If you can store your business process in XML, you can start to change business process by simply changing values in XML documents. We have customers that are already experimenting with that strategy." Versant’s customers in the financial and telecommunications sectors are already deploying XML as part of their business-to-business solutions. "Our customers are using XML to do more than exchange data," Sehgal says. "They are using the technology to track and manage information flows -- almost like workflow tools within a single organization, but now enabled between business partners."

In addition, every major database vendor is committed to accepting and issuing XML documents as a feature of their databases. This means that an elderly order processing system based on IBM’s DB/2 can talk directly to a new, Internet-enabled order entry system based on Microsoft’s Site Server, Commerce Edition. That is, as long as they understand each other.

Scheming to Succeed

As XML becomes accepted as a standard, vendor-neutral approach for business-to-business communications, one issue will rise in importance: a standard definition of the tags and attributes used for business applications. Many industry sectors are banding together to build industry-specific XML language definitions, or schemas. The W3C has made it clear that while it is interested in seeing XML widely deployed, it does not want to get into the business of setting standards for specific industries. The result is a plethora of industry organizations and standards bodies that are trying to build momentum for their own XML schemas.

Some industries have been successful in defining XML schemas. For example, Rosettanet is an initiative by more than 30 companies in the personal computing industry to define an XML schema that defines all the properties of a personal computer. Rosettanet, which includes manufacturers such as Compaq Computer Corp., Hewlett-Packard Co., and Intel Corp., defines a common business language that can link the entire PC industry’s supply chain.

The risk of W3C's approach, however, is that different groups will create different standards for the same industry. A recent report by Zona Research Inc. ( warns that this is happening in key areas of electronic commerce. The report points to competing schemas in e-commerce, including the Internet Open Trading Protocol (IOTP) and Open Buying on the Internet (OBI). Microsoft’s Turner thinks that there will be an explosion of schemas as XML gains popularity, but he is optimistic about the end result. "After awhile, however, this will settle down and the eagerness that leads to the enthusiastic development of schemas will settle down and people will eventually start to agree on a known set of common ones," he says.

As schemas proliferate, many will share common tags and attributes. Marie Wieck, director of technology at IBM’s network computing software division, believes standards will emerge for cross-industry schemas. "There will naturally be a bit of consolidation here," she says. "I think projects like OASIS will result in a common set of e-business XML standards for common needs like EDI (electronic data interchange), message routing, and business-to-business commerce requirements."

If industry-specific schemas emerge and fuel the adoption of XML in business-to-business e-commerce, trading partners will quickly get used to exchanging XML documents to send and receive requests for data. EDI was supposed to fulfill that function between businesses, but its cost and complexity kept it from all but the best funded companies. A response to this problem has been the development of EDI tools and capabilities using XML. Still, experts agree XML will coexist with, not replace, traditional business-to-business electronic commerce solutions. "People aren’t walking away from EDI," IBM’s Wieck says. "Instead, they’re using the Web for those occasions when a transient connection makes sense. Others will continue to use EDI and add XML-based capabilities to the older systems. It shouldn’t be a ‘rip and replace’ model."

Despite XML’s advantages for business-to-business e-commerce it still has some warts. Because it is a markup language, it lacks support for processing. XML needs to be augmented with processing, whether scripting or programming, to manipulate the data once it gets to its destination. Organizations will also need a mechanism to query XML data in the same way that we use SQL to query information stored in databases. A standard has been proposed, called XQL, but it is not yet final.

XML and the Future of B2B

Along with preparations for deployment of Windows 2000, IT organizations have XML high on their project lists this year. A recent industry study of 300 Fortune 1,000 IT executives showed that nearly half surveyed had XML on their planned project list for 2000. The vendor community is listening.

When asked about the use of XML within Microsoft, Turner chuckled and replied, "Just try and find a place inside Microsoft that isn’t using it. I’m not aware of any product -- other than those in the home and entertainment groups -- that isn’t having XML capabilities built into feature sets."

IBM’s Wieck agrees: "We have more than 500 people actively engaged in building solutions based on XML."

According to Wieck, there is a method behind all this XML madness. "There’s enormous attention being paid to business-to-business electronic commerce today," she says. "XML is the core technology that will fuel the growth of e-business. The next generation of business-to-business electronic commerce will bring IP standards to the Web and connect people, business processes, and the Web together. XML is fundamental."

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