Hello Mathew and Chris,

I think that was a very interesting discussion! We do have some examples from traditional modeling world. ( class room kind of examples..)

For example, A Supervisor is an employee himself, and he has staff ( group of employees ) working for him! Which creates a one to many relationship !

MW: I’m afraid that really is only a class-room example. In the real l world, the employees and supervisors come and go, so it is really a many-to-many relationship, and arguably more complex even than that.

A meetup of Meetups has similar modeling notations..

About your previous slides.. and the exmaples of Table.

At a conceptual level ( Ontology) I would just have a superclass, a class of "Furniture"

with subclass as Tables, Chairs, upholstry and the rest in the list.. and relationships..

MW: Upholstery is not a class of furniture. It is only a part of a piece of furniture.

As one can see, Class "Furniture" can be generic and standardazised with a set of generic subclasses and generic relationhips.. if one does not include the exceptions, at this level, I would find that acceptable. it can be done at a detail level.. as long as superclass covers all.. However, if one finds the exceptions or the special types ear;y, then can include as notes with explanation, it would help at a detail level.

MW: If there are exceptions, then you have just done something wrong.

At a detail design level - which is logical and physical, I would include further details and exceptional or special types etc.. But at a detail level of design, if this step is overlooked, it causes either design flaws or difficult coding to cover it up. ( its just bad design..)

MW: I’m sorry, I don’t follow this. Specific product models may be subtypes of generic product types.

Regards

Matthew West

Information Junction

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