Maintaining Consistency of Data on the Web

A common problem in designing and maintaining a Web site is that data on a Web page often replicates or derives from other data, so-called base data, that is usually contained in other Web pages or legacy systems such as relational databases. Upon changes in the base data, replicas and derivations need to be updated accordingly. However, since there are no technologies available on the market that provide such a functionality, Web pages are often inconsistent. For example, after assigning a thesis to a student and modifying the Web page that describes it in detail, the thesis is still incorrectly contained in the list of offered thesis, missing in the list of ongoing thesis, and missing in the advisor's teaching record.§This work presents a solution by proposing a combined approach that provides for maintaining consistency of data in Web pages that (i) replicate data in relational databases, or (ii) replicate or derive from data in Web pages. Upon modifying base data, the modification is immediately pushed to affected Web pages. There, maintenance is performed incrementally by only modifying the affected part of the page instead of re-generating the whole page from scratch.