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

From: Bob Badour <bbadour_at_golden.net>
Date: Sun, 16 Feb 2003 13:46:24 -0500
Message-ID: <AmR3a.85$dV5.14819377@mantis.golden.net>


"Lauri Pietarinen" <lauri.pietarinen_at_atbusiness.com> wrote in message news:3E4E7C35.9010800_at_atbusiness.com...
> It might be interesting to note that Dataphor makes a clear distiction
> between relations and result sets that are returned to the user
> (or program etc...):
>
> We would have the relational expression
>
> emp OVER {salary} WHERE deptno = 1;
>
> and then when it is returned we have
>
> SELECT emp OVER {salary} WHERE deptno = 1 ORDER BY salary;

I have to say I like this better than SQL, and I think it obviates the distinctions leading to Paul's comments. In Dataphor, the unadorned relation express is always a relation, and the operation to convert the data to an external physical representation requires an explicit SELECT keyword. It's clearer when different things look different.

> Quota queries look like this:
>
> emp OVER {salary}
> WHERE deptno = 1
> RETURN 10 BY {salary desc}
>
> so also making a distinction between ordering and
> quota queries.

I think this is much clearer and easier to use than some of the quota query specifications I have seen. (I guess TOP...ORDER BY is a proprietary SqlServer extension?)

It's very clear that one can output the results in a different order:

SELECT emp OVER {salary} WHERE deptno = 1 RETURN 10 BY {salary desc} ORDER BY surname; Received on Sun Feb 16 2003 - 12:46:24 CST

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