: XML in the Enterprise

Feb. 28, 2000 12:00 AM

Welcome to <e-BizML>! Some of you may be familiar with my e-Java column in SYS-CON Publications' Java Developer's Journal. I'd like to continue <e-BizML> in the same flavor by focusing on the business aspects of XML in the computing industry. Similar to e-Java, I'll offer my two cents on an XML (or related technologies) book in this and subsequent issues. I want to make this column as interactive as possible and would appreciate any feedback from you, the reader.

Let's talk about what we're going to talk about in this column in the coming year. We'll discuss, for example, XML's role in e-business today, and new and exciting events taking place in the world of XML. And as they emerge, I'll provide overviews of specific new technologies and discuss their impact on the XML industry. Our focus here is on XML in e-business - hence the moniker <e-BizML>.

I'd like to start by examining how the term metadata is used in the industry and how it relates to XML. We'll look at some of the common areas in distributed enterprise applications that can leverage XML and related technologies. We'll also look at an organization that helps fund XML projects in the computing industry. I'll end with a review of the e-book for this month - XML Pocket Reference.

Let's Start with Metadata
Metadata is often referred to as "self-describing" data. In other words, it's data that describes data. It defines a common language that allows data to be shared among people, systems, processes and programs, resulting in more effective communication. All organizations have their own terms and definitions that facilitate communication. However, the same term may mean something else in another context. For example, a "chip" refers to something edible (very much so) in the food industry, and something different in the electronics industry. At the same time, different terms in different contexts may be used to refer to the same entity. For example, a "Customer" in one organization may be a "Client" in another.

When different terms are used to refer to the same data, interpretation and maintenance of that data becomes complex. Metadata defines a common language used within an enterprise or an industry consortium so that processes and programs within that enterprise (or industry consortium) can communicate using a common base for the data definitions. For example, the title, release date and singer's name constitute metadata that describes a music album or CD. The songs themselves may be viewed as the content or the data.

A Metalanguage for Defining Metadata
Markup languages provide a means to document metadata in computing. XML is a markup language used to create conceptual documents in the form of character strings. The format of the document is defined by marking up the content of the document based on a set of well-formed rules. Metadata is used to define the structure of an XML document or file. The language rules are in the form of a DTD (document type definition) that in turn follows the rules of XML. As XML is used to define other languages (such as DTDs), it is thus, by definition, a metalanguage (a language that defines other languages).

XML provides a much-needed standard in the way firms exchange and present information over the Internet. It does so by facilitating computer-to-computer communication via the use of standard data formats. These formats are standard across a specific business realm or environment. Metadata that's used by various industries can be used within XML to define markup vocabularies. XML serves as an enabling technology that facilitates integration of structured and unstructured data for e-commerce applications.

Applying XML
Okay, XML is a neat technology that allows us to communicate using standard data formats. That doesn't say much for how it can contribute to business applications. In a nutshell, XML promotes an extensible environment in which data can be exchanged in a standard manner. This can contribute to a variety of enterprise application areas. Following are some of the areas in business computing in which XML is currently making an impact. They're listed randomly, without regard to any order of importance.

Deployment descriptors for runtime: A natural fit for XML is its use as a mechanism for defining deployment descriptors for an application's runtime environment. XML can be used to replace the paradigm of configuration files that are hard to maintain, static and not very portable. Software components can be deployed with accompanying XML descriptors that offer more sophisticated runtime capabilities by using XML's metadata description capabilities. For example, this mechanism has been adopted by the Enterprise JavaBeans deployment model.

Information distribution: The Web has created a revolutionary way of disbursing information from disparate sources to a multitude of participants in a distributed environment. This is because it offers a pervasive distribution channel by leveraging the Internet. XML technology is based on the premise that content and presentation should be separated when exchanging information. This makes it easy to distribute the content and leave the presentation of the content up to the client application. Of course, XML provides the mechanism (XSL) for data presentation also. Nevertheless, end applications have the option of processing the content without presenting the data in a browser. DTDs that accompany the data enable applications to offer more structured and "intelligent" information.

Enterprise data management: Enterprise applications require the exchange of heterogeneous data; it may come from different data sources, in the form of various formats and transferred using a variety of communication protocols. This leads to a substantial requirement to integrate the data so that applications can use it. XML provides a universal representation of data for information exchange between applications. It does so by facilitating data sharing and communications between different applications and customizing the presentation of the data.

Business transactions and data transformation: Besides being the Web standard for exchanging data, XML is also becoming the standard for business transactions. This is especially true in legacy environments. For example, whenever data needs to be migrated between dissimilar systems, data transformations are required. XML offers a standard format for transporting data in the middle tier.

Business process workflows and data integration: Business process workflows consist of sub-workflows and processes from various organizations within the enterprise. This leads to a requirement to integrate the data from these processes. The data may be in different formats. XML offers a viable option as an integration technology in that it facilitates data interchange. Standardization of XML-based workflow systems will ensure that different workflow systems can exchange business process information using XML as a medium for data exchange.

Knowledge management: XML acts as a facilitator in knowledge management by coordinating the interpretation of disparate data. XML DTDs provide a mechanism for modeling knowledge as well-formatted structures. The extensibility of XML and the flexibility of DTDs enable application developers to transfer knowledge between different applications using standard data interchange formats. This also enables applications to export data from existing legacy document formats and to extend these documents by wrapping them with metadata, which is defined using XML.

Searching and pattern matching: XML enables information to be accessible in a highly structured form. Its extensibility lets applications define custom tags that enable more sophisticated and complex searches. Again, the mechanism for this is the metadata that can be expressed using XML. XML's enabling the data to be described in a hierarchical structure also enhances the capabilities to recursive searches, parametric searches, and so forth.

Application integration: XML provides the infrastructure for inputting and outputting documents containing metadata. This metadata promotes a common vocabulary for data interchange between different applications, thus enabling them to integrate with other applications. XML also facilitates information aggregation by defining common data formats in which information sources can receive and aggregate data from various sources.

Personalization and content management: XML enables presentation of customized content for different users, depending on their preferences and business interactions. XML enhances the personalization capabilities of e-commerce applications because it's very effective in managing structured information. Indeed, that's the salient functionality offered by this technology. Thus XML can be used for creating and managing data structures that can be customized effectively for different users. The structures can be reused in different environments, which makes any proposed solution inherently scalable. In a similar manner, XML supports data syndication, content replication and management.

Messaging and data transport: A misconception regarding XML is that it's also a means for data transportation. A more accurate description of the role played by XML in data transportation is that it facilitates the definition of common message formats that allow messages to be exchanged between different applications. Consequently, XML can make use of exchanging transport protocols for data interchange.

Funding XML Projects
Although XML as a new technology has garnered all the hype typically associated with computer-related technologies, the computing industry is still struggling with areas in which XML can be leveraged to provide solutions. Since XML impacts several areas of computing, several innovative ideas for leveraging its capabilities will start emerging in different organizations within a company. When a technology is at such a stage, it always helps if it finds a patron who will nurture ideas and help them grow. And it always helps if the patron backs this up financially.

One organization that helps fund XML projects is XMLFund, a venture fund in Seattle formed in 1999 by David Pool, a veteran in Internet start-ups. I hope to interview David in a forthcoming issue of XML-J so readers can learn more about the fund and its mission. This organization plans to invest exclusively in companies that are working with XML technology. It's based on the same principles as the Java Fund, an organization funded by California-based Kliener Perkins Caufield & Byers that focused exclusively on Java technologies. Some of the companies that have been funded by XMLFund are Nimble.com, Digital Counterpart, and PhotoTrust.com.

Marking Up
XML, in my opinion, is going to be a key technology that will help the computing industry meet the demands of e-business for the next generation of computing. Its acceptance or rejection will depend heavily on how XML standards mature in the next year and how widely they're accepted. I hope this column helps you understand the role, developments and acceptance of XML in e-business in the years to come.

<e-book>
This month's XML book, XML Pocket Reference by Robert Eckstein, is the first one I've looked at in O'Reilly & Associates' Pocket Reference series. At first glance it's what it says it is - a small, pocket-sized reference that's easy to carry in your pocket or organizer. It's a well-organized and concise reference for basic XML concepts. After a brief introduction to XML and its relationship to HTML, the author defines XML terminology and the basic structure of XML documents. Chapter 2 is a reference to XML itself; Chapter 3 serves as a reference for DTDs. The remaining chapters cover XSL, XPointer and XLink. The coverage is concise, to the point, and written in a clear, easy style.

Pocket Reference is an introductory text for the reader new to XML. It may also serve as a reference when you're going out to a technology discussion and want some conceptual clarifications. To my mind, that's what this book should be used for. A reader familiar with XML will probably need a reference with more detail, examples and detailed descriptions. However, at $8.95 and 107 pages, you won't lose anything by keeping this one handy as a quick reference to XML concepts.

About Ajit Sagar
Ajit Sagar is a principal architect with Infosys Technologies, Ltd., a global consulting and IT services company. Ajit has been working with Java since 1997, and has more than 15 years experience in the IT industry. During this tenure, he's been a programmer, lead architect, director of engineering, and product manager for companies from 15 to 25,000 people in size. Ajit has served as JDJ's J2EE editor, was the founding editor of XML Journal, and has been a frequent speaker at SYS-CON's Web Services Edge series of conferences, JavaOne, and international conference. He has published more than 125 articles.