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--- Chiusano Joseph <chiusano_joseph@bah.com> wrote:
> George,
>
>
http://lists.xml.org/archives/xml-dev/200308/msg00222.html
>
> You might like to go through this archived thread
I like the thread (well, the incarnation of the
permathread) surrounding
http://lists.xml.org/archives/xml-dev/200306/msg00174.html
. In this post, Paul Prescod brings together a lot of
the characteristics of document/narrative and
data/record-oriented schemas.
Clear, unambiguous "definitions" of the two terms is
probably impossible. Likewise, most serious schemas
contain both categories of markup. One can, however,
identify criteria that tend to distinguish one from
another. Think of them as prior probabilities in a
Baysian classifier or parameters in a fuzzy set
membership function :-) The ones I think best
distinguish the two (from several posts, especially
Paul's) are:
- "Document" XML is used to mark up narrative text
intended to be read by humans; "data" XML is used to
exchange database records intended to be processed by
machines.
- Instances of "document" XML are readable without the
markup; instances of "data" XML are meaningless
without the markup.
- "Document" XML generally allows mixed content;
"data" XML generally does not
- The order of sub-elements almost always matters in
document-oriented XML; in data-oriented XML it
generally matters only for elements specifically
identified as "lists" or something similar.
- Document-oriented applications can generally deal
with unknown markup by removing the markup and keeping
the content; data-oriented applications generally deal
with unknown markup by ignoring the unknown markup and
its content.
- [quoting directly from Prescod] "Data-oriented
systems tend to prefer object types to be detectable
independent of context (thus namespaces) whereas
document processing is typically done top-down
recursively so relying on context is natural."
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