Under the guidance of Professor Carlo Zaniolo I’m currently work on schema evolution and Temporal Databases. Every Information System (IS) is subject to an uninterrupted evolution process aimed at adapting the system to changing requirements. One of the most critical portions (of the IS) to evolve is the data management core.
Often based on relational database technologies, the data management core of a system needs to evolve whenever the revision process requires modifications in the set of data or in the way they are stored or maintained, e.g., to increase performance. Given its fundamental role, the evolution of the database underlying an IS has a very strong impact on (all) the application(s) accessing the data, and support for a graceful evolution is of paramount importance nowadays. The complexity of database and software maintenance, clearly, grows with the size and complexity of the system.
Furthermore,when moving from intra-company systems, typically managed by rather small and stable teams of developers/administrators, to collaboratively-developed and -maintained public systems, the need for a well-behaved evolution becomes indispensable. In this web-scale scenario, due to its collaborative nature and fast rate of growth, the forces driving a system to change become “wilder”, while stability, shared agreement, and evolution documentation become crucial. This part of the research is thus devoted to the effort of developing methodologies and tools to support seamless database evolution by means of query rewriting and migration support.
Within this context we developed two systems: PRISM, a system to support schema evolution in relational snapshot databases, and PRIMA:a system to support data archival and querying under schema evolution.