Re: Love or hate, or? domains with cardinality two

On 2015-11-09 23:33:52 +0000, Gene Wirchenko said:

I was arguing about how schemas like that are commonly found in

practice, and about how I feel uncomfortable with them, because, let

apart the obvious difficulties with enforcing some integrity constraints

(e.g., a department should have one and only one manager at a time) in

     Invalid assumption.  I do some inventory counting and have seen

references in stores to co-managers.  The store has more than one

store manager (not just managers of different ranks).

And I have seen departments where the assumption (at least, the "only one"

part) is valid. Anyway, the point is not whether the assumption is realistic

or not, but what the implications are.

     And what obvious difficulties?

If you think there aren't any, show me a straightforward solution (of

course, what is difficult and what is not is largely subjective!).

Nicola

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