User-centric Enterprise architecture captures organizational information, analyzes it, and classifies it, and serves it up to the end user in useful and usable ways to enhance decision-making.
I came across a helpful article in DM Review, May 2008, called “Ontology and Taxonomy” that clarified the classification schemas used in EA.
First of all what the heck is a classification schema?
Simply put, a classification schema is a way of organizing information by putting things into categories. This helps us make sense of the information by being able to relate items to one another. For example, is an item, part of a larger supertype? Does an item has subtypes? Are items part of a common set? Is there a one to one relationship, a one to many, or a many to many? An understanding of these relationships between information helps us to understand the information and better use it for sound decision making.
Here are the two classification schema:
- Ontology—“includes putting things into categories and relating these categories to each other…an ontology is a model…’ontology concerns itself with the organization of knowledge’…the body of knowledge includes both class and instance.” Ontologies define relationships. In ontologies, we identify the intersection of different items with each other, so for example a man intersects with “person,” “male,” and “adult.”
- Taxonomy—“A taxonomy is an ontology in the form of a hierarchy.” Typically, taxonomy takes the form of a tree diagram, with parent (class) and child relationships. Taxonomies are decompositions. “For example, a parent may be automobiles and the children may be trucks, SUVS, sedans, compacts, and so on. Then the children for trucks may be pick-ups, vans, refrigerated, etc.
One of the problems with taxonomies is that you cannot easily define everything neatly into categories and subcategories, such as in cataloging a body of knowledge. For example, in the Dewey decimal system, “Where do you put a book about the history of mathematics in the Islamic world? History? Mathematics? Religion? That points out the problem with most taxonomies. Most of our knowledge is not hierarchical.”
The limitation of taxonomies is why we need to use more sophisticated ontologies such as business, data, and system models in enterprise architecture to understand the complexity of the relationship between business processes, information required to perform those, and the systems that serve those up.