Re: SQL for Modeling Generalization Hierarchies
Date: 02 Jun 2004 16:57:33 GMT
Message-ID: <20040602125733.647$6f_at_newsreader.com>
robertbrown1971_at_yahoo.com (Robert Brown) wrote:
> > >
> > > This solution does not seem to scale since for each value of
> > > "discriminator" I need to perform a join with a different table. What
> > > if I need to retrieve 1,000 employees at once?
> >
> > Why would you ever need the attributes of more than one subtype? If
> > your query is about doctors, why would you need to join the table
> > about janitors into the query?
>
> Because I need to display users and their heterogenious attributes in
> the UI as one list (e.g. in response to a search).
Uh, that isn't really an answer.
> > If your query is about employees, why would you need to know any of the
> > subtype attributes?
>
> Same reason, our customer's HR department does not see the employees
> as separate entities. To them an employee is an employee and they want
> to see all the associated data while browsing employees. I guess you
> could show the generic attributes on the first pass and then require
> the end user to click to drill down and see the subtype attributes -
> but that's not what they want.
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