Re: Relation problem

 wrote:
> On 23 Jan 2001 12:25:06 GMT, hidders_at_REMOVE.THIS.win.tue.nl (Jan
> Hidders) wrote:
>
> >I am not sure I understand this. If an organization is deleted/inserted
> >then you also have to delete/insert it in the Parties table, otherwise
> >referential integrity is compromised.
>
> Assuming that Parties is the supertype, you delete an organization by
> deleting a row from the table Parties (and by logically cascading
> that delete through the foreign key references in other tables).
> Deleting a row from Organizations removes a detail about the
> organization, not the organization itself.

Sure, but then you are dropping the constraint the the Organization table is the union of the two "subtables". That's fine as long as you are clear about what every tuple in every table means.

-- 
  Jan Hidders

PS. Can I ask you to set the 'full name' of your postings somewhere in
    you newsreader/poster? The attribution of your text now looks a bit
    awkward.