Master the three parts of tuning an Oracle database: data modeling, SQL code tuning and physical database configuration. A data model contains tables and relationships between tables. Tuning a data model involves nNormalization and dDe-normalization. Different approaches are required depending on the application, such as OLTP or a Data Warehouse. Inappropriate database design can make SQL code impossible to tune. Poor data modeling can have a most profound effect on database performance since all SQL code is constructed from the data model. Poorly written SQL code is often a culprit in performance problems and is expensive to rectify. However, tuning of SQL code is generally cheaper than changing the data model. SQL code tend to be contained inside independent blocks within applications or stored procedures.