Connected Data Objects  Connected Data Objects (CDO) is a free implementation of a Distributed Shared Model on top of the Eclipse Modeling Framework (EMF). With CDO, programmers can easily enhance existing EMF models in such a way that they can be stored and subsequently maintained in a central model repository. While object relational mapping against a JDBC data source on the server side is the shipped default, CDO provides for "pluggable storage adapters" that allow you to develop and use different mappers (like Hibernate- or OODB-based). On the client side, CDO provides a default integration with EMF, the Eclipse Modeling Framework, although other model integrations on top of the "CDO protocol" are imaginable as well.