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RE: merge mode for XML


From: Glew, Andy
Subject: RE: merge mode for XML
Date: Wed, 1 May 2002 13:33:08 -0700

[Greg Woods]:
>... conversations about XML and DTDs ...
> ...
> "well formed" by definition should mean in conformance to a 
> pre-existing DTD!
> ...
> Do you build relational databases without defining a schema?  

Well, I wrote Perl-SQL, a relational database system that
is self-schematizing - where every record can define its own schema,
with its own fields.

Motivation: schema changes in most existing relational databases are
onerous.
Even just adding fields is painful. Self-schematization allows new fields to
be
added on the fly, improving documentation of the experiment results 
that are my target data, because any observed features can be easily added
to the schema in a structured way.  As opposed to all of those database
schemas
that have a miscellaneous text or comment field, where far too often all the
critical data that you wish to process lives. Self-schematization allows you
to
do all SQL operations across spontaneously added fields.

---

3-4 years ago I discussed self-schematization with Prof. David Dewitt, a man
of some
reknown in database circles.  His take is that self-schematization was not 
done in the early days to save space, and that now it is not unreasonable to
do so.

However, rather than Perl-SQL, he pointed to me towards XML, saying
something
like "well formed SQL doesn't require a schema or DTD -- that is the
future."

---

I.e., Greg, not all RDBMS experts agree with you about schemas; ditto DTDs.



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