I. Sourikova (BROOKHAVEN NATIONAL LABORATORY)
To benefit from substantial advancements in Open Source database technology and ease deployment and development concerns with Objectivity/DB, the Phenix experiment at RHIC is migrating its principal databases from Objectivity to a relational database management system (RDBMS). The challenge of designing a relational DB schema to store a wide variety of calibration classes was solved by using ROOT I/O and storing each calibration object opaquely as a BLOB ( Binary Large OBject ). Calibration metadata is stored as built-in types to allow fast index-based database search. To avoid a database back-end dependency the application was made ODBC-compliant (Open DataBase Connectivity is a standard database interface). An existent well-designed calibration DB API allowed users to be shielded from the underlying database technology change. Design choices and experience with transferring a large amount of Objectivity data into relational DB will be presented.