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Re: Relation problem

From: Jan Hidders <hidders_at_REMOVE.THIS.win.tue.nl>
Date: 22 Jan 2001 10:11:33 GMT
Message-ID: <94h10l$dkb$1@news.tue.nl>

 wrote:
> On 21 Jan 2001 00:26:30 GMT, hidders_at_REMOVE.THIS.win.tue.nl (Jan
> Hidders) wrote:
>
> >I am afraid that these magic words also don't make the problem go
> >away. :-)
>
> Depends on what the problem really is. See below.
>
> >This supertype is a generalization of Individuals and Organizations.
> >That means that every Party is either an Individual or an Organization.
>
> It means that one table, Parties, takes the place of the tables
> Individual and Organization at their original level of abstraction.
> Attributes common to individuals and organizations move from those
> tables into the table Parties.
>
> It also means that one FK for the table of party addresses no longer
> comes from either of two domains (Individuals or Organizations), it
> comes from just one--the table Parties.

Of course, but it also means that you will still have two tables Indiv. and Organ. that contain the class specific attributes and a foreign key to the Parties table. And the reverse of this foreign key is a "split foreign key".

> >And that is what the original problem was.
>
> I don't think so. Maybe Michel will jump in and make it clear.

That would certainly be helpful.

-- 
  Jan Hidders
Received on Mon Jan 22 2001 - 04:11:33 CST

Original text of this message

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