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Re: views of binary operations

From: erk <eric.kaun_at_gmail.com>
Date: 17 Jul 2006 04:51:58 -0700
Message-ID: <1153137118.774748.137380@i42g2000cwa.googlegroups.com>


Aloha Kakuikanu wrote:
> Marshall wrote:
> > Consider named views of binary operations on relations.
> >
> > Given a relational operator "op" and relation variables A and B,
> > and a declaration of:
> >
> > r = A op B
> >
> > the language evaluates the expression "A op B" and assigns the
> > result to r.
> >
> > However, if we declare this as a view, ...
>
> View is a named expression. r is a view.

I don't think so - although it depends on the semantics of Marshall's mini-language, his "view(r)" syntax seems fairly clear. r is a snapshot, assigned the value of "A op B" based on the current values of the relvars A and B at the time the assignment is made.

Received on Mon Jul 17 2006 - 06:51:58 CDT

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