GNOME-DB can be taken of as an extension of the libgda project. Its aims are the same: to provide universal data source access for client applications, as well as development tools and libraries for doing so. GNOME-DB is an extension to libgda because it adds support to the architecture for the GNOME project.
Both projects were once together under the GNOME-DB project, but libgda was separated from it due to its great usefulness also outside of GNOME environments. All GNOME dependencies were removed when performing this separation.
But GNOME-DB is not just a front-end to libgda for the GNOME project. Thus, making use of the different GNOME technologies, such as Bonobo, XML , GConf, etc, it extends libgda in a way that allows for awesome database-related GNOME applications. Through the use of Bonobo , the GNOME component system, a whole range of services and utilities are provided in the form of components, thus allowing their reuse in other Bonobo-aware applications. In fact, this is the way the communication is done with the other applications contained in the GNOME Office suite.
It provides libraries to be used in developing GNOME-DB applications, and lots of tools and utilities to help you in all your database-related tasks. It also includes a development environment to speed up the development of applications based on GNOME-DB.