Dynamic Data Analysis on the Web-a Design Approach
Learn about an adaptable approach which separates programming tasks from Web page design tasks. This strong conceptual model encourages good design, enables re-use of data definitions, and is well-suited to the construction of dynamic user interfaces. The authors also illustrate the particular challenges you might encounter when you dynamically change the analysis performed by Web pages. (This intermediate-level article was first published by IBM developerWorks, August 5, 2004, at http://www.ibm.com/developerWorks).
In a multi-disciplinary Web application development team, the fulfillment of several roles need to occur, one of which is that of the page author. This role typically includes HTML or JavaServer Pages (JSP) editing, graphic design, and scripting. An experienced page author knows how to present information effectively while conforming to relevant standards. When it comes to defining data analyses and accessing the results, a programmer is usually required. Our design approach capitalizes on the best skills of each role, and brings the complex task of data analysis and results access within the scope of the page author, while leaving the details of the data access to the programmer.
Online analytical processing (OLAP) applications use a data model that provides an abstraction of the underlying data that separates the definition of the data access and aggregation mechanisms from the selection, presentation, and exploration of the data. Therefore, an OLAP-like model is particularly well-suited to separating the roles of programmer and page author. Full-scale OLAP engines offer a huge range of features for slicing, dicing, and aggregating data, but as with many complex systems, the majority of users only need a relatively small subset of these features.
We will discuss the most commonly used OLAP features and describe a simplified OLAP-like conceptual model. The use of the model will be the foundation for a set of custom JSP tags for page author use.