Re: 4 the FAQ: Are Commercial DBMS Truly Relational?
Date: Sun, 10 Oct 2004 08:21:02 -0400
Message-ID: <E5-dnVBQ9KTctPTcRVn-qg_at_comcast.com>
> I think it *would* be a set - in a truly relational system, the SELECT
> would automatically do de-duplication. i.e. every SELECT would be the
> equivalent of existing SQL's SELECT DISTINCT.
In retrospect, I think it would have been nice if "SELECT" had done what
"SELECT DISTINCT" does.
Anyone who really wanted to keep the duplicates could have said "SELECT
ALL".
Consider "UNION" and "UNION ALL".
Then there are the people who won't use SELECT DISTINCT "for performance reasons".
"Yes, but the answer is wrong", I say. They respond, "that's a minor detail."
There is a widespread belief in this field that wrong answers with good performance are closer to the goal line than correct answers with poor performance. I will never come around to that point of view. I almost always want to get it right, first, then work on getting it right, and fast. Received on Sun Oct 10 2004 - 14:21:02 CEST