This article is about only one of those choices, that is the layeringof an object-oriented class model on top of a purely relational database.This is not to imply this is the only, best, or simplest ...

Examples of object-oriented databases are ObjectStore and Versant Object Database. Relational databases have also added object-oriented features; for example, UniSQL was one of the first products ...

Object-oriented programming allows procedures about objects to be created whose exact type is not known until runtime. For example, a screen cursor may change its shape from an arrow to a line ...