Re: Mixing OO and DB

From: David BL <davidbl_at_iinet.net.au>
Date: Thu, 14 Feb 2008 18:31:56 -0800 (PST)
Message-ID: <1c8db931-775c-47d5-be69-1f643e4f78ec_at_e10g2000prf.googlegroups.com>


On Feb 14, 10:38 pm, JOG <j..._at_cs.nott.ac.uk> wrote:
> On Feb 14, 3:52 am, David BL <davi..._at_iinet.net.au> wrote:
> > On Feb 13, 9:56 pm, JOG <j..._at_cs.nott.ac.uk> wrote:
> > > On Feb 13, 2:06 am, David BL <davi..._at_iinet.net.au> wrote:
> > > > On Feb 12, 9:53 pm, JOG <j..._at_cs.nott.ac.uk> wrote:

[snip]

> > > Another example:
> > > "todays lottery numbers: 23, 34, 17"
> > > "experimental reults: 23, 34, 17"
>
> > > Same values, different data. If you agree with this statement then
> > > values != data surely?
>
> > You seem to have forgotten that I said data was associated with the
> > appearance (ie encoding) of values.
>
> Nicely dodged, but let me try again!
>
> "todays lottery numbers: 23, 34, 17"
> "experimental results: 23, 34, 17"
>
> All written down on a bit of paper - same values discussed, but
> different data. Agree or disagree?

I agree. Yes, same values but different data

> I ask this because if we can distinguish data and values, we must then
> determine /how/ they are different. You state it is by "encoding" but
> the two lines above are encoded in the same manner as far as I am
> concerned, so that cannot be the difference between the two concepts.
> That is unless your "Encodings" equates to my notion of "Facts", and
> we are thus agreeing loudly, using different definitions of those
> terms.

They are the same values and they are encoded in the same manner. However they are distinct appearances, hence distinct data.

[snip]

> > Do you agree you cannot formalise what the values represent?
>
> Yes, imo no "meaning" can be represented via a purely descriptive
> formalism. One always needs some component situated in the real world
> for that. But obviously we can formalize communicated statements of
> fact.

I would say facts can be formalised to the extent that within a context a tuple can be assumed to represent a fact. But strictly speaking within the formalism tuples themselves are really just values.

[snip]

> > > This seem overly philosophical to me. Surely we don't need metaphysics
> > > to know that if someone hands me a bit of paper with: "1.00, 0.376 and
> > > 0.904" on it, well that's just a list of values. However if if someone
> > > hands you a bit of paper with "Surface Gravity - Earth:1.00, Mars:
> > > 0.376 and Venus:0.904", or tells you those denotations, then we have
> > > data ;)
>
> > You have repeatedly chosen examples that suit your argument, whereas
> > according to our disagreement only I that have that privilege!
>
> > Jim:
> > In all examples, data is useful to the recipient and
> > represents facts
>
> Yes, of course, because the poem example is much harder for me to deal
> with ;P
>
>
> > David:
> > 1) In all examples, data is useful to the recipient and
> > represents values; and
> > 2) There exists example where data is useful to the recipient
> > and doesn't represent facts
>
> > Since a tuple of a relation is a value and it also represents a fact
> > it is clear that my definition of data encompasses yours.
>
> > We can both easily think of examples where (so called) data is useless
> > to the recipient. Let's agree and say that's not actually data. That
> > only leaves one possibility for proof by counter example: I provide
> > an example where the data is useful to the recipient yet doesn't
> > convey any facts. The sending of a poem or an image without any
> > additional context is an example.
>
> Well put. I contend that you can't do this, and that a poem or image
> as described is not an example of data, but merely values. You are
> saying to me "a poem is data. It is clearly not a fact. Ergo, pwnage."

In this discussion I would prefer to actually say "the appearance of a poem is data".

> But you are already assuming it is data in the first step. I say its
> not, and cannot follow why you would think it is. Like a "22". That's
> not data but, if I was a numerologist say, I would still find the
> value interesting.

I keep thinking you're ignoring my qualification that it is the appearance of a value that counts as data, not the value itself.

> So to me the poem is just a value.

Yes, but would you say the appearance of a value is just a value?

> Its only data when I say this thing
> here, X, has role Y.

We agree that a value doesn't have a context. However the appearance of a value *does* have a context.

> A picture is just a picture. Even if its, say, a
> biochemistry picture of a cell membrane. _However_ if that picture is
> then put in a log book, under "image of neurostem cell from experiment
> B", its data. This accords to tradtional definitions.

You seem to have three distinct arguments.

  1. Data requires knowledge in order to decode it as a value; and this knowledge is part of the data.
  2. David has been saying data = value; and a value (is just a value and) doesn't have a context; and a conveyed value without a context is meaningless.
  3. by definition data = encoded values that represent facts; so an encoded poem (with no additional context) is not data

Please tell me if I've misrepresented you!

I would say (1) doesn't actually lead to any differences in practise over what we call data, making it appear rather metaphysical.

In my opinion (2) can be defeated for two different reasons

  1. David has actually been saying data = appearance of value; and an appearance of a value has a context
  2. there exists examples (like a poem) where a conveyed value without any additional context is useful.

(3) leads to a difference on real examples, but I do find it surprising that I could give you a disk with a web page encoded on it and you would claim that it isn't actually data (but it may contain data).

> I am offering you examples where you have an item that you would not
> describe as data, and showing how it is turned into something that is
> generally described as data. All best, have found the conversation so
> far well articulated, even if we don't agree.... Jim.

Also the conversation has been courteous. Cheers! Received on Fri Feb 15 2008 - 03:31:56 CET

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