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Home -> Community -> Usenet -> comp.databases.theory -> Re: What predicates the following relation represents
>> 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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