Relational Data Tailoring Through View Composition

This paper presents a methodology to derive views over a relational database by applying a sequence of appropriately defined operations to the global schema. Such tailoring and composition process aims at offering personalized views over the database schema, so as to improve its ability to support the new needs of customers, support evolutionary software development, and fix existing legacy database design problems. The process is driven by the designer's knowledge of the possible operational contexts, in terms of the various dimensions that contribute to determine which portions of the global schema are relevant with respect to the different actors and situations. We formally introduce some operators, defined on sets of relations, which tailor the schema and combine the intermediate views to derive different final views, suitable for the different envisioned situations. The application to a case study is also presented, to better clarify the proposed approach.