Re: A different definition of MINUS, Part 3

vadimtro_at_gmail.com wrote:
> On Dec 19, 6:47 am, paul c <toledobythe..._at_oohay.ac> wrote:

>> Would you like try to your hand on the case where A and B have equal
>> headings and extensions to see if you get what I get?

I meant values like this:
A:
x y
1 2

B:
1 2
1 3

In my equations so far, A <AND> B for these values is the only non-determinate conclusion the A-algebra comes to (using my adjusted MINUS definition). Note that if B has only the 'tuple' (1, 2) I believe the result is determinate, ie. fine. (Strange as it may sound, I find both results re-assuring, even though I would not have predicted that last week!)

Thanks for your work-up, will try to understand as a cross-check of what I'm seeing. Am starting to see McGoveran's point, but if I've got it right, I think there is a better solution. Noe I'm thinking that the problem doesn't start with update, it starts with JOIN. Received on Fri Dec 19 2008 - 20:16:23 CET