Re: Nulls, integrity, the closed world assumption and events

Marshall wrote:
<snip>
> Sure. And since you are of the opinion that theory can steer us down
> the wrong path, and since you regularly deprecate relational theory
> but do not provide an alternative *theory*, I wonder at your presence
> in a theory newsgroup.

If I had another comprehensive theory, I would not have so many questions or opinions that I want to pass by those who can correct me. I typically write here to learn, where I write in my blog to teach or prompt some creative thought on a topic. If one must come to cdt with all questions answered, then you are right that I should not engage in dialog here, or at least not with those who think along those lines.

> > In that case, there are surely many mathematical theories that have
> > been applied, and there are choices to make on when to employ what
> > theory. Both two and three-valued logic are theories that can be
> > applied to databases, for example. Discussing which one to use, how to
> > choose one, etc would seem to me to be appropriate in a database theory
> > forum. So, I would think this would be a place to discuss what makes
> > the most sense for databases. Do I have this wrong?
>
> Your attribution of 3VL to relational theory is wrong,

I do not attribute it to relational theory, except to the extent that it entered into the profession pretty much as part of all implementations of relational theory of which I am aware. 3VL is theory, however, right? I'm getting a definition of your use of the word theory as mathematics combined with its application. If I am understanding that better now, then surely there is a theory of 3VL applied to databases. Perhaps it is simply named 3VL and is a theory that rode in on the coattails of relational theory.

> for example; the
> two are independent. (Actually some here would probably argue that
> they are antithetical, even.) Your attribution of of a proscription
> against
> nesting to relational theory is also wrong.

Yes, I have learned from this forum and elsewhere that some still hold 1NF (and most still teach it) as being about non-simple domains or so, but that others do not. Again, it is relational theory that seems to have led to the large installed based of the form-formerly-known-as-1NF, the lack or poor implementation of lists (ordered bags of tuples of dim 1 or higher), and the use of 3VL that are the most troubling to me, while the metadata repository (catalog) and strong typing are some of the other topics of interest. If none of these topics has anything to do with any database theory or theories, then perhaps there is another classification of these topics. Since I have not been posting much of late and have seen many of these topics arise repeatedly, perhaps cdt should write a FAQ to make more clear which topics are off-limits for the list.

> These are attributes of
> SQL,
> not the relational model; I observe that you often omit the
> distinction.

I am interested in that which has resulted from the introduction of "relational theory" and whether those parts of the implementations that I think have not served the profession well are related to the implementation of the theory, the misimplementation of the theory, or the implementation of some other theory. I'm not planning to develop new theories, but am happy to learn about changes to relational theory or any other theories that better align with what I have experienced as best practices (recognizing others have different experiences and not finding much in terms of emperical data).

It seems like 1NF, as most would still interpret that term, was a result of the proper implementation of relational theory as it was understood at the time. It sounds like some still think it proper while others disagree. I find that discussion interesting as well.

I do recognize that my questions are _about theory_ and its implications for databases and related software development rather than _within theory_ which is why I have taken to infrequent posting of late. It does seem that I am not the only one interested in such topics, however, and those who are not interested could certainly avoid such topics, if that is OK with you. Otherwise if we, as a group, want to draft something about what is off limits as topics, I will try to be a good citizen and abide by such. Thanks. --dawn Received on Mon Jan 15 2007 - 04:29:21 CET