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Re: Extending my question. Was: The relational model and relational algebra - why did SQL become the industry standard?

From: Bob Badour <bbadour_at_golden.net>
Date: Fri, 14 Feb 2003 00:00:33 -0500
Message-ID: <B3%2a.1428$%h4.170851448@mantis.golden.net>


"Mikito Harakiri" <mikharakiri_at_ywho.com> wrote in message news:tQY2a.19$O%2.129_at_news.oracle.com...
>
> "Bob Badour" <bbadour_at_golden.net> wrote in message
> news:RHY2a.1418$0T3.169406528_at_mantis.golden.net...
> > I wonder why someone would request:
> >
> > select SUM(SAL) from (
> > select SAL from emp
> > )
> >
> > when one wants the sum of all salaries.
>
> <user's logic>
> I want the sum of all salaries. There are a lot of confusing columns in
the
> Emp view, but I think that all the columns other than Sal are not
important
> for the question I'm asking. Therefore, let's project them away. Now I'm
> adding up all the salaries. Why the hell am I short of $100K?
> </user's logic>
>

Frankly, I think you are stretching your user's logic beyond the credible. All those confusing columns are irrelevant to

select SUM(SAL) from emp

which is almost as simple from the user's perspective as is

select SAL from emp

Your example assumes your users lack sufficient knowledge and training to formulate even the simplest of queries. If that is the case, they are as likely to get incorrect or incomprehensible results with a multiset dbms as with a relational dbms. Received on Thu Feb 13 2003 - 23:00:33 CST

Original text of this message

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