Data objects are part of the underlying data model that a diagram is based on. These objects are on the diagram palette in the Data compartment. When you delete a data object, you can either delete the object from both the diagram and the underlying model, or you can delete the object from the diagram and retain the object in the underlying data model.
In contrast, an annotation object (for example, a note) is not part of the underlying data model. When you delete an annotation object, you can only delete the object from the diagram.
To delete a data object from a diagram: