Design and Analysis of Active Hypertext Views on Databases

Abstract

The design and maintenance of data-intensive Web sites is a demanding task. The effort can be significantly lowered by using two verified technologies: databases and hypertexts. The first is well suited to administrate a large amount of data; the second has proven to be an easy to use and efficient means of accessing information. The task can be made even easier by using a declarative approach, i.e., the data structure and hypertext structure are both explicitly defined, and the specification is expressed in terms of structure transformation. In addition to the specification language, we provide a design technique: starting with the database structure, the designer applies refinement heuristics that eventually yield an efficient hypertext structure for the final user. The hypertext thus obtained can be seen as a view on the database. A fully functional hypertextual interface should also enable the user to perform update operations on the database. Our system provides this facility, including mechanisms to tackle the well-known update-through-views problem by providing specific mechanisms. Finally, the nonprocedural approach has a supplementary advantage: it offers the possibility of analyzing the hypertext structure before setting it in production, in particular, analyzing the reachability of information or determining the length of the navigation path.