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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: Jon Heggland <heggland_at_idi.ntnu.no>
Date: Mon, 4 Jul 2005 08:26:38 +0200
Message-ID: <MPG.1d32f5042340fdcb9896d6@news.ntnu.no>


In article <NBAxe.135734$rx6.7273595_at_phobos.telenet-ops.be>, jan.hidders_at_REMOVETHIS.pandora.be says...
> >>Not really, I'm restricting it slightly. I'm using the one that says
> >>that a value is something that (1) has one or more representations,
> >>i.e., can be encoded in memory and (2) is identified by that encoding in
> >>the sense that some equivalence relation over all possible
> >>representations is defined and each value corresponds to an equivalence
> >>class defined by it.
> >
> > This sounds just like D&D's definition in TTM. But a lexical object is
> > not a value, it is the representation of a value? What then is a lexical
> > object *type*?
>
> A set of values.

Let me try to sum up.

A value has one or more representations. A lexical object is a representation, not a value. A lexical object type is a set of values. Thus, a lexical object is not a member of a lexical object type.

Right?

-- 
Jon
Received on Mon Jul 04 2005 - 01:26:38 CDT

Original text of this message

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