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

From: Jon Heggland <>
Date: Mon, 4 Jul 2005 08:26:38 +0200
Message-ID: <>

In article <NBAxe.135734$>, 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.


Received on Mon Jul 04 2005 - 08:26:38 CEST

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