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Re: What predicates the following relation represents

From: --CELKO-- <joe.celko_at_northface.edu>
Date: 2 Apr 2004 15:49:08 -0800
Message-ID: <a264e7ea.0404021549.39ffdae6@posting.google.com>


>> It depends on the meaning given to the relation. <<

That is what I am trying to pin down with the idea of a "complete fact" ..

>> "At some point in time, we have sold a batch of PART of size SOLD."
<<

then I need that time to have my complete fact and I should add a timestamp column to the table.

>> "Have we ever sold a batch of 7 nuts?"; "Show me all the parts we
have ever sold as a batch of 10" <<

then I need something to mark that batch to have my complete fact. If what we are calling "sales" in this example ought to be "batch_size", then I have it. And my key would be both columns, as you said.

I always loved the informal idea of a "False Fact" versus a "True Fact" in practical reasoning. The "False Fact" statement "The pilot is sober today, so we will take off now" carries a lot of implications, even tho it is true. The complete facts might be that this pilot has a perfect flight history and has never had a drink in his life. Received on Fri Apr 02 2004 - 17:49:08 CST

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