Re: what are keys and surrogates?

From: rpost <>
Date: Sun, 06 Jan 2008 23:56:49 +0100
Message-ID: <b03d5$47815cb1$839b4533$>

JOG wrote:

>> >> >1) A 'Key' is a set of attributes, used at the logical layer to
>> >> >uniquely identify a proposition.
>> >> >2) An 'Identifier' is a set of attributes, used at the conceptual
>> >> >layer to uniquely identify an entity.
>> >> Why use two different terms?
>> >Because they apply to different things, propositions and entities.
>> >Don't confuse the two.
>> What is the difference?
>You can't distinguish between a statement of fact, and the things that
>are the subjects of those statements describe? Cor Blimey guvnor.

I can, and already explained how I do it; for me, the difference is essentially grammatical in nature, but you seem to have a different idea of how the distinction is made and what it means; hence my question.

>> For me, an entity is a proposition treated as a thing
>> (i.e. used as a reference rather than a description).
>Wuh-wuh? Its generally agreed that 'entity' is a synonym for
>'thing' (according to them dictionary jibjobs) so you seem have
>written: "an entity is a proposition treated as an entity". Er...

What I was trying to get at is that calling an entity a "thing" doesn't add any explanatory value to me. Worse, it makes things *less* clear, since many entities aren't actually "things". I find it much more clarifying to say an entity is something used as a reference.

>I'm starting to think this is a wind up ;) If so props indeed! The
>rest of what you have posted is [...] just so
>abrasive, well, I have to doubt the intentions behind it.

The tone was chosen with the intentions of communicating how reading that long discussion on "hidden" attributes you were referring to generally made me feel, and what I think of its overall quality; following that, I provided a pretty technical explanation why your statements above are muddy and unsatisfactory (that is, from *my* understanding of the issues and terminology), what my alternative definitions would look like, and why.

Clearly I was trying to do too many things at the same time there. Your response stops before the actual technical content of my reply starts. This has happened before (remember your list of paradoxes?) so I'm clearly failing to communicate effectively. My apologies.

>I don't really understand why you're so entrenched - I've explained
>the logic behind how using hidden attributes as keys can be
>deleterious, and I've given you some examples.

But you ignore my explanations on why these examples are irrelevant to the points I'm trying to make.

I don't feel entrenched, I just don't feel the points I've been trying to make all along are clear to you, so I keep trying to reword them.

There's a lot going wrong here, it seems. (If one of us were a systems analyst and the other the customer, I would be positively ashamed of myself.) Your definitions of terms (e.g. those above) still seem superficial to me, I appear to be missing critical parts; at the same time, you keep on posting remarks and questions from which it is clear that things I take for granted aren't known or assumed by you. E.g. most of what you wrote about "hidden" attributes is invalidated by a disagreement on what it means for an attribute to be hidden; most of your objections to my including entities, references and surrogate in the modelling language are incomprehensible because I cannot make out to what extent we agree on what an entity, reference or surrogate is. At the same time, there are many things we completely agree on. But as long as this kind of misunderstanding occurs, we can't have a very meaningful exchange of ideas. The only way I know of resolving that is to keep on trying. Then again, there are more important issues in the world, even to me.

Received on Sun Jan 06 2008 - 23:56:49 CET

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