Object-to-Relational (O/R) mapping:
There are various ways to persist data and the persistence layer is one of the most important layers in any application development. O/R mapping is a method of mapping data representation from an object model to a SQL based relational model.
O/R mapping is well suited for read, change, write centric applications and not suited for write centric applications where data is seldom read. Although this was usually true of many earlier O/R mapping frameworks, most today give for efficient paths of performing large batch style write operations. O/R mapping tools/frameworks give you to model inheritance, composition and association class relationships. O/R mapping tools work well in 85-90% of cases. Use basic database features like triggers, stored procedures etc, when O/R mapping is not appropriate. Keep in mind that no one shape fits all solution. O/R mapping tools/frameworks allow your program to be: