Re: Entities, Relationships, and Tables

"David Cressey" <david_at_dcressey.com> wrote:

[snip]

>I'm wondering about the opposite construction. It seems to me that if you
>think of relationships as being of order 2, 3, 4 etc.
>(binary, ternary, quaternerary, etc.), all you have to do is extend the
>concept downward one, to "unary relationships", and you can now think of
>your entity tables as being "unary relationship tables". I'm not sure
>whether the concept of "unary relationship" is a useful one or not. I
>rather suspect not, or else I think I would have seen it somewhere.

     One possibility is that an employee has a manager unless the employee is at the top of the heap. This is a unary relationship within an employee table.

[snip]

Sincerely,

Gene Wirchenko

Computerese Irregular Verb Conjugation:

     I have preferences.
     You have biases.
     He/She has prejudices.