This section describes the design of the HTML-based Diorama user interface accessible by World Wide Web clients such as Netscape [25]. The Diorama WEB user interface is made up of two components: (i) the HTML markup language (including frames) which the Netscape browser actually interprets and displays, and (ii) the underlying Perl CGI modules which are executed by the WEB daemon to fetch, transform, and normalize data, access other Diorama prototype modules or Oracle engine (through Oraperl), and return valid HTML code (new web pages) to display. Generally speaking, the Perl scripts are activated at client side, process data at sever side and return valid HTML code back to the client side browser for display. The following functionality was taken into consideration in the demo version of the Diorama user interface design:
One of the most interesting aspects of Diorama experimental implementation is the support for interactive query tracing and processing. During the processing of a long query, the user is presented with intermediate results and thus can monitor, or provide feedback to the system to guide, the next step in the processing of that query.