Re: A different definition of MINUS, Part 3

Cimode wrote:
On 19 déc, 19:37, paul c <toledobythe...@xxxxxxxx> wrote:
Cimode wrote:
[Snipped example]
<<As soon as they started
making premises, they lost me because it doesn't look like their
method is anything more than case analysis that have any chances to
be
scaled up to practical problems. >>
Precisely. I would go further as to say that hoping that using solely
algebra would be sufficient to achieve such resultis nothing more than
the holy graal of RL. As you mentionned in an earlier post, the
example of lack of quantifiersi is one major obstacle most current
DandD work seem to ignore without consequence or awareness of the
price to pay.
Regards.. .
I think around 1972 Codd wrote a proof that the algebra was logically
equivalent to FOPC, later others (I forget their names) corrected a few
errors and proved the equivalence. This is why I'm happy to try to show
things with the algebra, even though it can be tedious trying to see the
forest for the trees.

To my knowledge, Codd never mentionned that FOPC would be sufficient
to clarify RL. Choosing to work *solely* on that angle is a matter of
personal choice.

Regards...

I don't think that's what I said. I think Codd meant that his relational model obeyed (ie., is based on) both of FOPC and his algebra. The personal choice is whether one uses algebra or fopc not only to understand his model but to define it.
.

Relevant Pages

  • Re: A different definition of MINUS, Part 3
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  • Re: A different definition of MINUS, Part 3
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