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Home -> Community -> Usenet -> comp.databases.theory -> Re: Does Codd's view of a relational database differ from that ofDate&Darwin?[M.Gittens]

Re: Does Codd's view of a relational database differ from that ofDate&Darwin?[M.Gittens]

From: Jan Hidders <jan.hidders_at_REMOVETHIS.pandora.be>
Date: Sat, 25 Jun 2005 09:55:55 GMT
Message-ID: <LS9ve.129677$q_3.7089212@phobos.telenet-ops.be>


Marshall Spight wrote:
>
> I went through a big round-and-round on this on comp.lang.functional
> a few years back. You're right in that it is "commonly accepted"
> to lump both input and output together as things that break RT,
> but in fact, only input breaks it, by definition.

Just for my understanding, by "input" you mean "reading the global state" and by "output" you mean "changing the global state"? And by "break RT" you mean that the substitution of a variable with its value can change the semantics of the program, right? And are we talking about a closed system (only the program can change the global state) or an open system (there may be agents outside the system/program that can change the global state)?

PS. I notice a certain rise in temperature in the conversation, but at the same time I don't really see a big difference in your opinions. Could it be that the disagreement is largely on how to define certain terms?

Received on Sat Jun 25 2005 - 04:55:55 CDT

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