Apache OJB


Apache ObJectRelationalBridge is an Object/Relational mapping tool that allows transparent persistence for Java Objects against relational databases. It was released on April 6, 2005.
As of January 16, 2011 Apache ObJectRelationalBridge has been retired.

Features

OJB is an open source project.
It is lightweight and easy to use requiring simply configure two files to implement a persistence layer.
It is easy to integrate into an existing application because it does not generate code.
It allows the use of different patterns of persistence: owner, JDO and Object Data Management Group .

Functionality

OJB uses an XML based Object/Relational mapping. The mapping resides in a dynamic MetaData layer, which can be manipulated at runtime through a simple Meta-Object-Protocol to change the behaviour of the persistence kernel.

Configuration

At least two files are required to configure OJB: OJB.properties and repository.xml

Allocation

For mapping a 1-1 relationship, for example, you have two tables: person and account. In this case, a person has an account and vice versa.