Re: what are keys and surrogates?

From: Bob Badour <>
Date: Wed, 09 Jan 2008 11:06:19 -0400
Message-ID: <4784e2ed$0$19868$>

Marshall wrote:

> On Jan 8, 6:17 pm, David BL <> wrote:

>>On Jan 8, 9:26 am, JOG <> wrote:
>>In November I started a thread called "RM and abstract syntax trees"
>>in which I suggested that RM was poorly suited for the representation,
>>never mind manipulation of ASTs.
> Hmmm, I think I remember that. ;-)

>>The problem is that the only
>>reasonable way to represent the structure is to introduce meaningless
>>node identifiers. An important principle in the RM is that a tuple
>>should always represent a proposition that makes sense to the problem
>>domain expert, so I agree with you that we cannot allow hidden
>>identifiers. Therefore the RM cannot help but expose the node
>>identifiers for all to see.
>>Prolog is able to parse string expressions entered by users and build
>>and manipulate ASTs. Behind the scenes, nested functor expressions
>>are usually implemented using dynamically allocated nodes wired up
>>with pointers. However, as far as the programmer is concerned, only
>>unification is available to decompose the structure. It seems to me
>>that Prolog has a more general support for data modeling than
>>available in the RM, to the extent that nested functor expressions
>>avoid the need to introduce lots of meaningless identifiers.
> This issue goes away if we relax 1NF and allow attributes that are
> lists or relations. This gives us nested structures. (Nested relations
> are not particularly controversial around here.)

The straw man starts at: "the only reasonable way". Received on Wed Jan 09 2008 - 16:06:19 CET

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