At this point, you will see that
Author and
Columnist are at the same level (
siblings) in the hierarchy, while
News_Service and
Editor are subclasses of
Author. Conceptually, however,
News_Service,
Editor, and
Columnist are all at the same level of generality, while
Author is a more general concept. This goes against a principle of good ontology design:
all the siblings in a hierarchy (except for the ones at the root) should be at the same level of generality. Therefore, we want to modify our hierarchy to make
Columnist a subclass of
Author, which will more accurately reflect the underlying structure. To modify the hierarchy by making
Columnist a subclass of
Author:
- Click on Columnist and drag it over the Author class (Author will be outlined), then release.
-
Columnist is moved and now appears as a subclass of Author.
In this case, the mismatch may have been obvious. However,
when you create your own ontologies, the development process itself can reveal
differences or parallels that were not clear at the beginning. Therefore it is
likely as you go along that you will rearrange the hierarchy, as well as
create and delete classes, to better model the concepts you are trying to
capture.