You may need to switch from one database provider to another, or to upgrade the version of your database software. The latter case is less likely to require physical data migration, but this may happen with important updates. In these cases, a physical transformation process may be necessary as the underlying data format can change significantly. This may or may not affect the behavior of the application level, it depends largely on the fact that the data language has changed – but modern applications are written to be agnostic to database technology so that a change from SQL Server, MySQL , Oracle should only require a test cycle to be sure that both functional and non-functional performance has not been negatively affected.