What Are Object-Oriented Databases And Persistence?
See also Appendices B and E and the comp.databases.object newsgroup. Refs to be included in future FAQs. Object-Oriented Databases are databases that support objects and classes. They are different from the more traditional relational databases because they allow structured subobjects, each object has its own identity, or object-id (as opposed to a purely value-oriented approach) and because of support for methods and inheritance. It is also possible to provide relational operations on an object-oriented database. OODBs allow all the benefits of object-orientation, as well as the ability to have a strong equivalence with object-oriented programs, an equivalence that would be lost if an alternative were chosen, as with a purely relational database. Another way of looking at Object-Oriented Databases is as a persistent object store with a DBMS. Persistence is often defined as objects (and their classes in the case of OODBs) that outlive the programs that create them. Object lifetimes can
