The GnomeDbForm and GnomeDbGrid widgets both display data from a GdaDataModel, and, if the data model supports it, allow the user to make changes to the data. These widgets are structured in the same way, as described by the following UMLish diagram. They both implement the GnomeDbDataWidget interface.
Also both of these widgets are visually composed of a specialized widget (which actually display the data) and of a GnomeDbDataWidgetInfo widget which displays navigation and other action buttons, which is illustrated in the following diagram:
As illustrated on the UML diagram, the GnomeDbRawForm inherits the GnomeDbBasicForm which is a form which displays data contained in a GdaParameterList vector of values. The GnomeDbBasicForm can be used when the data to display is not in a GdaDataModel, such as when a couple of values are required to perform extra operation.