Re: [xml-dev] The privilege of XML parsing - Data types,binary XML and XMLpipelines (LONG)

["Roger L. Costello" <costello@mitre.org>]

Hi Sean,

> Having said that, I am not averse to data types. I'm averse to them
> being in the core where they infect everyone whether your like
> it or not. I'm advocating the use of a pipelined parsing paradigm
> in which datatype ornamentation of the tree is cleanly separated
> from the tree itself.

I think that I see what you are saying Sean, but I'd like to analyze this a
bit.  Let's take the aircraft example:

<?xml version="1.0" encoding="UTF-8"?>
<aircraft>
    <elevation>12000</elevation>
</aircraft>

There is no associated data model with this.  It is just a string.  It is this
form that gets transmitted from client to application?

When an application receives the above document it then "applies" a data model
to it.  For example, with xerces (Apache) it is possible to associate an XML
Schema (i.e., a data model) to an instance document at run time.

Is this the type of pipelining that you are referring to?

I have some questions about something that you said: "Applications come and go
but data lives forever".  I believe that when you say "data" you are referring
just to the string:

<?xml version="1.0" encoding="UTF-8"?>
<aircraft>
    <elevation>12000</elevation>
</aircraft>

and not to any data model that might be associated with this string.  Thus,
this string endures over time but not data models (or applications).  Right?

This seems a bit unsettling to me.  It is the data model that provides meaning
to the string.  The data model allows me to understand the aircraft and
elevation elements.   I would imagine that it is the combination of the data
and the data model which endure.  What are your thoughts on this?  /Roger