Three Access Language Paradigms

[Joe Lapp]

Derek Denny-Brown <ddb at criinc.com> wrote:
>I am not sure that the term "document" is clearly defined for your usage.

I guess I did overuse and under-define the word 'document.'  I'll try to
convey what I intended to mean.  I understand that pretty much any well-
formed construct can serve as a document in XML.  I also understand that
we might want to talk about a single document that consists of multiple
documents that are linked together.  However, in my post I intended the
word 'document' to mean a single XML file or any system that makes itself
appear as if it were analogous to an XML file, such as a database that
exposes DOM IDL :-) interfaces.  That's the meaning I was using, though
I realize that it's probably not the best definition to work with.

In light of your response, I see that this is kind of a constraining
definition.  However, I think the language of my posting can be amended
so that it still has general applicability.  The word 'document' might
be taken in its most general sense, so that it applies to anything you
might think of.  Next, everywhere I talk about the DTD of the document,
we'd have to modify that to talk about the set of DTDs and structure
of links by which documents of those DTDs are intended to be linked.

>[...]  There are no
>"Documents residing on servers", but only documents which are generated as
>part of a interchange protocol.  Or do you mean that there are documents
>(A) (which may not be XML) and then there are XML "documents" (B) which are
>generated as part of the protocol to interchange the documents (A)?

Boy I really was being quite inconsistent.  When I talk about the protocol
messages being documents I was talking about a single serializable stream
of well-formed XML.  I guess I really was quite confusing.

>[...]  CORBA is great for a simple (to
>formulate & express) query which a server has to think hard about and can
>eventually deliver a simple (to express) answer.  XML is excelent for
>situations where either the query or the responce is not so easily
>simplified, and structured data interchange is desired.

XML seems to remove the client's responsibility for constructing complex
objects from primitive ones.  The object arrives complex already.  I agree.
Another side-benefit is that complex requests and responses can be batched
and transmitted over single short-lived connections.

>[...]
>Another thing which XML solves when used as a protocol is the problem of
>adding information to an existing protocol without breaking existing
>implementations.  This is a serious concern.

I didn't even think of that.

>[...] With regard to the
>protocol issue, we now have a MIME-ish thing with extensibility!

Nor did I think of that, but this may be because I'm more familiar
with mimes that play charades than mail-protocol MIME.

>So the point of my responce, is that some of the ideas in your original
>most strike a significant cord with my own ideas, but that the language for
>a discussion of these topics is not clear.

The language does need to be cleaned up, and I'd certainly appreciate
any help I can get.  Let me know whether this post clears things up any
or whether it further muddies the waters.

>There is also an problem that the real requirments for what you (Joe) are
>trying to do are extremely fuzzy at this point.  A clearer language for
>talking about this is needed (clarify some terms) and the requirements of
>what you are trying to do need to be specified more clearly.

I know.  They are fuzzy in my brain too.  I'm working on that one.
I've got something up there, but it is proving to be a very slippery
beast (with fangs and horns and a ferocious roar!).

--
Joe Lapp (Java Apps Developer/Consultant)
Unite for Java! - http://www.javalobby.org
jlapp at acm.org

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