Re: Surrogate Keys: an Implementation Issue
Date: Sun, 30 Jul 2006 15:47:42 GMT
Brian Selzer wrote:
> "paul c" <toledobythesea_at_oohay.ac> wrote in message
>> Brian Selzer wrote: >>> "paul c" <toledobythesea_at_oohay.ac> wrote in message >>> news:g9Nyg.263082$iF6.250988_at_pd7tw2no... >>>> Brian Selzer wrote: >>>>> What's the point of a database if it doesn't reflect some aspect of >>>>> reality. ... >>>> To talk precisely about whatever we want to talk about. Nothing more. >>>> Doesn't need to be real. >>>> >>> Agreed. But even a conceived universe subsumes certain absolutes, such >>> as time. >>> >> In that case, the statements in the database should talk about time, ie., >> aspects of time. These are different from statements about the time it >> takes the database to say something. >>
> There can be no discussion without time. Relational assignment cannot exist
> without the concepts of before and after. And the truth of a statement
> belonging to the database state that existed before an assignment depend on
> the circumstances that obtain before the assignment, which may no longer
> remain after.
No, it doesn't depend on 'circumstances'. Assuming variables, as you are, the truth of a statement depends on the value of the relation that is assigned to a variable.
p Received on Sun Jul 30 2006 - 17:47:42 CEST