Chapter 9. Building Applications

eXist is a great platform not only for storing and querying XML data, but also for building web applications. Returning pages in (X)HTML is a breeze, since XHTML is XML and XML is eXist’s bread and butter. Conveniently, because your data is in XML and the programming language is XML-aware, there is no “impedance” between the layers (data storage, processing, presentation). Piece of cake, isn’t it?

Well, maybe a marketing department (if one existed) would try to sell you this high-tech fairy tale. But as we all know, programming is hard work, whatever your environment or toolset. Silver-bullet environments don’t exist.

However, that being said, eXist does represent an excellent platform on which to build web applications. For applications that work with XML (or can be redesigned to work with XML), increases in development speed and decreases in code base size are often realized when compared to undertaking the same projects in Java or PHP for example. It’s not a panacea, but it can certainly help you in specific situations.


A web application is an application that is accessed over the Internet (or an intranet) and uses a web browser as its client. URLs passed from the browser are mapped to something on the server (a static page, a script that accesses a database, a CSS file, an image, etc.). Together this constitutes some meaningful functionality to the application’s users, such as accounting, playing games, or making friends. An application ...

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