Re: compound propositions

From: paul c <toledobythesea_at_oohay.ac>
Date: Mon, 15 Mar 2010 22:20:59 GMT
Message-ID: <fpynn.68195$Db2.35162_at_edtnps83>


Bob Badour wrote:
> paul c wrote:
>> Bob Badour wrote:
...
>> not knowing its purpose any more than a dbms designer can predict the
>> exact purpose some unknown db is used for, other than to say
>> intersection and quantification are involved. If you mean 'internal',
>> that which an algebra operates with, it is basically the expression
>> 'Customer[id] join Client[id]', standing for the intersection of the
>> set of Customer id's that match Client id's and vice-versa.

> 
> Actually, for join it is "'id' is a customer and a client". For union, 
> it would be "'id' is a customer or a client".
> ...

Thanks. The nuance I'm detecting here is that there is some useful reason for phrasing an internal predicate in English rather than the more formal algebra.

Am pondering the significance of the other comments. Received on Mon Mar 15 2010 - 23:20:59 CET

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