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

"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 - 23:08:48 CET