Labrinidis, AlexandrosRoussopoulos, NickA WebView is a web page that is automatically created from base data, which are usually drawn from a DBMS. A WebView can be either materialized as an html page at the web server, or virtual, always being computed on the fly.<p>For the materialized case, updates to base data lead to immediate recomputation of the WebView, whereas in the virtual case, recomputation is done on demand with each request. We introduce the materialize on-demand approach which combines the two strategies, and generates WebViews on demand, but also stores the results and re-uses them inthe future if possible.<p>Deciding on one of the three materialization policies for each WebView is clearly a performance issue. In this paper, we give the framework for the problem and provide a cost model, which we test with experiments on a real web server.en-USwebdatabasesviewsmaterializationwebviews,Technical Report