Re: Codd's Information Principle
From: paul c <toledobythesea_at_oohay.ac>
Date: Sat, 07 Nov 2009 01:08:42 GMT
Message-ID: <uM3Jm.50844$Db2.43500_at_edtnps83>
Date: Sat, 07 Nov 2009 01:08:42 GMT
Message-ID: <uM3Jm.50844$Db2.43500_at_edtnps83>
Tegiri Nenashi wrote:
...
> Likewise, relational calculus quantified expression
>
> exists y : R(x,y)
>
> is essentially a disjunction
>
> R(x,1) <OR> R(x,2) <OR> R(x,3) <OR> ...
> ...
In the spirit of the recent precision, it doesn't look to me like 'R(x,1)' et cetera are sets of tuples, which I believe '<OR>' requires. Shouldn't that '<OR>' be logical 'OR'? Also the result doesn't look 'truth-valued', shouldn't it? Received on Sat Nov 07 2009 - 02:08:42 CET