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

From: Alexandr Savinov <>
Date: Fri, 17 Jun 2005 11:04:00 +0200
Message-ID: <42b29202$>

Jan Hidders schrieb:
> Alexandr Savinov wrote:

>> Jan Hidders schrieb:
>>> Are you sure you are not talking about the (rather old) idea that is 
>>> commonly known as "the universal relation assumption" or "the 
>>> universal-relation data model"? For a few references see:
>> I find the problems raised in UR model very similar to those 
>> motivating COM. However, the provided solution is hardly acceptable 
>> (it is typcially relational). In COM we have advantages of UR model 
>> but the solution is based on other principles.

> Yes, you also seem to have added a little frame logic (e.g. see F-logic)

I read something about F-logic but I did not like it. Especially I do not like the way how they unify classes and objects. It is one of fundamental issues and their solution does not seem to be acceptable, imo. But may be I need to make the second pass...

> and concept lattices into the mix. Both are well-known and useful

I am very well familiar with concept lattices (if you mean formal concept analysis). There is some relationship betweeen COM and FCA but they different in goals and methods. The similarity is in use ordered sets as fundamental constructs for describing data (in contrast to other approaches including the RM). In COM we also assume that the order plays a fundamental role for describing data and its semantics. (Wihtout the order explicitly represented and managed our database is simply a storage.)

> theories, but hardly replacements of the relational model. For references:


Received on Fri Jun 17 2005 - 11:04:00 CEST

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