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

From: Jan Hidders <jan.hidders_at_REMOVE.THIS.ua.ac.be>
Date: 13 Feb 2003 17:39:07 +0100
Message-ID: <3e4bca2b.0@news.ruca.ua.ac.be>


Lauri Pietarinen wrote:
>>
>>The book is agnostic on this issue. It's starting point is that you want to
>>build an SQL database (and so there are duplicates in your results) and then
>>explains how you should do that.
>
>OK, thanks.
>
>So the answer to my question is
>"they have taken SQL as a basis _in_this_book_

Yes.

>but probably agree otherwise that duplicates should be avoided

Yes.

>and better optimisations would be obtained without duplicates"

No. In fact, in theory, all optimizations that can be done in a set-based algebra can also be done in a bag-based algebra but not the other way around.

Received on Thu Feb 13 2003 - 10:39:07 CST

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