Extensible utility: implementing XML for databases - Internet

Computer Technology Review, August, 2002 by Anupam Singh

Many companies today can easily exchange critical data with their employees, but when a partner or customer needs the same information, delays, inaccuracies and mistakes plague the process. Solving this problem raises concerns about preserving significant investment in database systems, establishing uniform operating procedures among business associates and optimizing, rather than replacing, current resources.

Until recently, the solution was a pricey and complex Electronic Document Interchanges (EDI) network. But the development of extensible Mark-up Language (XML) and efficient tools to support and process this language offer an economic alternative to sharing data. Using XML technology, companies can enhance the way they share information among orders, inventory, and production to help partners communicate throughout the supply chain and respond directly to changing market conditions. Incor-porating XML into relational database management systems (RDBMS) makes them more versatile, robust and effective. Additionally, XML is also used for storing data or archiving transactions.

In the early 90s, EDIs offered one-to-one transaction capability, but complex integration and high price tags prevented widespread adoption. The need to effectively process volumes of semi-structured data and transactions on the Internet drove the development of XML, a nimble, robust, and effective alternative to EDI. Both machine and human readable (EDI is only machine-readable), XML adds a layer of intelligent communication, enabling disparate applications to talk to each other. Subsequently, more organizations can transact business online without large software applications or resources, constant upgrades, and/or system overhauls.

Benefits of XML

Because XML is an orderly, easy-to-use specification for describing information, it delivers a universal data interchange format, easily shared between different systems. In such an agreement, trading partners can leverage XML to issue product catalogs to suppliers, who in turn may transform the product data stored in a back-end database to XML, rapidly interpret the information, and deliver it to buyers via their Web application. The seamless integration of internal and external systems improves the process of applications and organizations interaction over the Internet.

XML also supplies the ability to embed business descriptors along with raw data, thereby providing a common format for businesses to exchange information over the Internet. For example, a financial institution's customer wants to know which stocks were sold during the last quarter in Argentina for more than $100. This should not require the financial company's IT department to write a new process to collect this information; it should be able to be done immediately. In an XML-driven environment where the trades are in XML, the IT department should be able to use the RDBMS to store and index the XML. Subsequent queries over these XML documents should use the index to answer arbitrary queries.

To ease processing, XML has several internal mechanisms that insure the structure of an XML document: document type definitions (DTDs), XML schemas, and XML namespaces. Developers use these mechanisms to define the rules that process data. XIvIL processors use DTDs to determine the validity of a document. XML schemas enable the developer to require that documents contain specific data types for tags, as well as create user-defined complex data types, data ranges, and masks. XML namespaces leverage tags created from other developers even if they have the same name. By basing the identification of the document on the context of the tag rather than the name itself, documents with identical tags can still be processed according to their appropriate functionality.

Adoption of XML

In the past year, XML has emerged as the de facto standard of encoding information for document, interchange but implementing, optimizing and extending its use seems risky and expensive to potential users. While they realize they must handle an increasing quantity of XML-formatted data, customers are comfortable with their data in an RDBMS engine and their data processing in packaged applications, investing significant resources in making the applications and the database interact effectively. The ideal XML solution will capitalize on that investment and improve its functionality, without requiring a massive conversion effort, and will integrate seamlessly with the RDBMS that contains the business information--resulting in current, accurate information, which enables informed and efficient business decision-making.

To understand the effect of real-time collaboration, consider planning a vacation to New York City. It would be quite convenient to logon to a travel website, enter a budget, travel dates, and a few preferential details (non-smoking room, late check-out, full-size rental car for the trip upstate, etc.) and have an entire customized vacation delivered via email within minutes. If the flight were cancelled, the travel service would reroute you through the most convenient location and convey the change via a previously indicated method (cell phone, PDA, email, etc.). To provide such a service, the system must not only capture the data, but also store it in a format easily accessible in real time by all affected parties and transform it into another format for interaction with the affected parties. This implies a standard data format to facilitate exchange of information between different companies, and a highly efficient store and search mechanism.