Re: O'Reilly interview with Date

From: mAsterdam <mAsterdam_at_vrijdag.org>
Date: Tue, 09 Aug 2005 23:01:14 +0200
Message-ID: <42f9197a$0$11077$e4fe514c@news.xs4all.nl>

Marshall Spight wrote:
> erk wrote:
>

>>How can "data" not be structured in some way? Given your comments, I
>>have no clue what "semi-structured" actually means - although I
>>probably didn't before either.

>
> Just a quick note: a now believe that the term "semi-structured"
> does actually have a legitimate use, although I will grant that
> most usages of the term one sees are not using the term in any
> formal way.
>
> "Semi-structured" data refers to data in a context where some
> of the structure of the data is visible to the application, and
> some is not.

Maybe "Semi-structured" has a raison d'être but this isn't it.

From the point of view where structure is invisible, the data is atomic, individable. The structure is invisible. Non-atomic data (maybe the same signs viewed with a different 'lense') has visible structure and parts. Now: is the data structured, or not, or maybe semi-structured? No - the (semi-) structuredness is in the point of view, not in the signs.

> For example, if you have a network packet with a header and a
> payload, you might have an application that knows the schema
> of the header but not the payload, and uses data in the header
> to choose an encryption method for the payload. The application
> treats the payload as an opaque stream of bytes, hence it is
> "unstructured" to that application. Of course, the structure
> is still there, and some other application down the line will
> know what the schema for it is. Clearly, if *no* application
> knew the schema, it would just be noise and not data.
>
> I was surprised to discover that this term actually can be
> useful.

Hm... I did not have this surprise yet :-)

> Knowing a useful definition of the word also makes
> it clearer when one encounters a non-useful use of the word.
> Lots of low-end XML people use the term to mean, "I don't
> know what schemas are for."

:-) Received on Tue Aug 09 2005 - 16:01:14 CDT