Re: How to represent types of people

See my answer in comp.databases.

"Kev" <kevin.porter_at_fastsearch.com> wrote in message news:3A2E282F.EE503743_at_fastsearch.com...
> Hi,
>
> I have a design question I hope someone can help me with...
>
> I'm designing a database, a part of which needs to represent different
> types of people, 'different types of people'
> meaning 'people with different jobs'. So, I have made a 'Job' entity on
> my ERM and a 'Person' entity. I have
> a third entity called 'Person_Job' which represents an instance of a
> person's employment. Person_Job stores
> a start and end date too.
>
> The problem I'm having is that different types of people need to have
> different relationships with other
> entities in the system. For example, I cannot simply add a relationship
> labelled 'Plays for' between
> Person_Job and the Team entity, because although that would be correct
> for a player it would not be
> correct for a manager, and there are other relationships which are true
> for a manager but not for a player.
>
> What is the correct way of dealing with this situation on an ERM? And,
> what is the correct way of
> implementing it?
>
> thanks,
>
> - Kev
>
Received on Wed Dec 06 2000 - 15:36:19 CET