Tuning of SQL code is generally cheaper than changing the data model. Physical and configuration tuning involves a search for bottlenecks that often points to SQL code or data model issues. Building an appropriate data model and writing properly performing SQL code can give 100 per cent + performance improvement. Physical and configuration tuning often gives at most a 25 per cent performance increase. Gavin Powell shows that the central theme of "Oracle10gR2 Performance Tuning" is four-fold: denormalize data models to fit applications; tune SQL code according to both the data model and the application in relation to scalability; create a well-proportioned physical architecture at the time of initial Oracle installation; and most important, mix skill sets to obtain the best results. It is fully updated for version 10gR2 and provides all necessary transition material from version 9i. It includes all three aspects of Oracle database tuning: data model tuning, SQL & PL/SQL code tuning, and physical plus configuration tuning. It contains experienced guidance and real-world examples using large datasets and emphasizes development as opposed to operating system perspective.