Re: Another view on analysis and ER

From: TroyK <>
Date: Fri, 7 Dec 2007 11:49:53 -0800 (PST)
Message-ID: <>

On Dec 7, 9:12 am, "David Cressey" <> wrote: [snip]

> What's the difference between a predicate and a proposition?

I like C.J. Date's explanation for this: "Observe, incidentally, that a proposition can be regarded as a degenerate predicate; to be precise, it's a predicate for which the corresponding set of parameters is empty (and the function thus always returns the same result, either TRUE or FALSE, every time it's invoked). In other words, all propositions are predicates, but most predicates aren't propositions."

"The Logic Of Business Rules", "Practical Database Foundations" paper.

TroyK Received on Fri Dec 07 2007 - 20:49:53 CET

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