| Apache ObJectRelationalBridge | |
| Collapsible: | yes |
| Developer: | Apache Software Foundation |
| Latest Release Version: | 1.0.55 |
| Operating System: | Cross-platform |
| Programming Language: | Java |
| Genre: | Object-relational mapping |
| License: | Apache License 2.0 |
Apache ObJectRelationalBridge (OJB) is an Object/Relational mapping tool that allows transparent persistence for Java Objects against relational databases. It was released on April 6, 2005.[1]
As of January 16, 2011 Apache ObJectRelationalBridge has been retired.[2]
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 (PersistenceBroker API), JDO and Object Data Management Group (ODMG).
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 (MOP) to change the behaviour of the persistence kernel.
At least two files are required to configure OJB: OJB.properties and repository.xml
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.