XML, what for? (2/2) - exploring XML
XML, what for?
Most database APIs are defined in a particular programming language, so that results are returned in that language's native data types. While Standard Query Language (SQL) is a widely accepted (not quite standard) method for specifying the database "question," there is not yet a language-independent and database-neutral specification for the "response."
Most database vendors work on XML add-ons for their products, so that result sets are returned in XML form, separating rows and columns with corresponding tags. These results can then be turned into display information using XSL or some other transformation method.
Inter-application data exchange
Today many different applications exist in organizations, and most of them do not talk to each other. This way much time and effort is wasted on duplicate data entry and data integrity checking. In addition, the Web has created a world-wide infrastructure for communicating between applications (the Web server and the system behind it) and users (the person sitting behind the Web browser). This communication system can also be used between applications to exchange messages in a secure manner across the Internet. HTTP is the only protocol with decent firewall support, and since messages in XML format are plain text they can be transmitted as they are.
While text-based formats are less compact than binary representations, the human-readability of those messages make expensive tools for encoding and decoding them obsolete. Published DTDs can be the basis for software development with standard XML tools like parsers, editors, and XSL processors. In the future hopefully all software systems will come with built-in support for XML-based import and export of data.
XML is useful for many tasks outside the direct Web context, in Office documents, searching and indexing applications, databases and data exchange. In combination with the Web technologies we can achieve interoperability across application and organizational boundaries. Let's break down those barriers using XML!
Created: Sep 10, 2000
Revised: Sep 10, 2000