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

From: Steve Kass <skass_at_drew.edu>
Date: Tue, 18 Feb 2003 17:24:42 -0500
Message-ID: <b2ubo9$6s2$1_at_slb9.atl.mindspring.net>


Can you be more specific? What operation on what object cannot be implemented by a physical model faithful to the logical multiset model? Or are you making a different claim?

SK

Alfredo Novoa wrote:

>"Mikito Harakiri" <mikharakiri_at_ywho.com> wrote in message news:<8BT2a.11$O%2.25_at_news.oracle.com>...
>
>
>>"Alfredo Novoa" <alfredo_at_ncs.es> wrote in message
>>news:e4330f45.0302130552.5f51736a_at_posting.google.com...
>>
>>
>>>I only want to add that duplicates also ruin updateable views.
>>>
>>>http://www.pgro.uk7.net/views3_0110.htm
>>>
>>>
>>Why? View updates is about ability to solve equations with relational
>>operators. While one can certainly claim that Set Algebra is superior to
>>Bag Algebra, you have to demonstrate what exact technical difficulties are
>>solving equations in the Bag Algebra.
>>
>>
>
>The systematic approaches to the view update problem based on
>predicate logic does not work with bags.
>
>
>Alfredo
>
>
Received on Tue Feb 18 2003 - 23:24:42 CET

Original text of this message