Re: Does Codd's view of a relational database differ from that ofDate&Darwin?[M.Gittens]
Date: Fri, 1 Jul 2005 22:02:15 -0400
Message-ID: <5IWdncc2pt00aFjfRVn-tg_at_comcast.com>
Hi,
[...]
"Jan Hidders" <jan.hidders_at_REMOVETHIS.pandora.be> wrote in message
news:IVhxe.135039$l56.6861917_at_phobos.telenet-ops.be...
> Jon Heggland wrote:
>> Anyway, there is one thing that is bugging me when I read articles about
>> object data models like Calvanese/Lenzerini and Van den Bussche /
>> Paredaens. If objects are just identity points, and the properties of
>> objects are other objects, where do actual data values enter into the
>> picture?
>
> Data values are special objects that have one or more representations
> associated with them by which they are identified.
What's that supposed to mean ? 'Value' is just an element of a domain (data type), like, say, '1' is_a_member_of Integer. Are you proposing a new definition of 'value' ? If so, what is it ? The above is not a formal definition by any stretch of imagination.
>Like LOTs and NOLOTs in NIAM.
I looked briefly at LOT/NOLOT. Did not see much of [formal] defonitions though. Could you please provide a reference or reproduce one ?
[It's not idle curiosity on my part (as was with the 'return' word). I am genuinely interested what the current formalism for the object/network/xml data model is.]
Thanks.
>
> -- Jan Hidders
Received on Sat Jul 02 2005 - 04:02:15 CEST