Re: A foreign key on a self-referring table

"mAsterdam" <mAsterdam_at_vrijdag.org> wrote in message news:404a1860$0$573$e4fe514c_at_news.xs4all.nl...

> +------------------+
> | Reports_To |
> +------+-----------+
> | EMP# | MGR_EMP# |
> +======+===========+
> | 2 | 1 |
> | 3 | 1 |
> | 4 | 3 |
> | 5 | 2 |
> | 6 | 3 |
> | 7 | 2 |
> +------+-----------+
>
> , the predicate being
>
> "Employee with number (EMP#) reports to employee with number (MGR_EMP#)"
>
> Aside: There is a reason why I still would not have
> this in a real database:
> What if a managerspositon is vacant? But
> that may be another topic.

Well, it changes the functional dependencies; we now find that employees report to a department, not to a manager, and the OrganizationChart relates departments, not employees. Received on Sat Mar 06 2004 - 21:10:30 CET