Re: algebra equations for Reference and FD constraints

From: paul c <>
Date: Mon, 29 Dec 2008 14:45:23 -0800
Message-ID: <Uoc6l.37887$lX6.30793_at_newsfe06.iad>

paul c wrote:.
> ...
> The reason for adjusting <RENAME> has to do with the inability of
> A-algebra syntax to form a relation R'{a,a1} from R{a}, such that each
> tuple has two triples with the same 'v' value.
> ...

Sorry, that is a stupid statement that I thought I edited out.

> One way to get that ability is to replace the <RENAME> operator with,
> say, a <DUP> operator whose definition varies like so - the line:
> ...

I should have said <DUP> is just a shorthand. I'm still not sure that <REMOVE> and <RENAME> are all that's needed in the A-algebra beyond the operations that parallel the Boolean ones, but it sure looks that way so far. Maybe I'll have to learn the calculus to be more sure. Received on Mon Dec 29 2008 - 23:45:23 CET

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