[XML4LIB] Databases or XML

Elizabeth Shaw ejshaw+ at pitt.edu
Thu Feb 7 14:01:59 EST 2002


Hi

A very good article that talks about XML and Databases by Ronald Bourret
is available at:
http://www.rpbourret.com/xml/XMLAndDatabases.htm
It is a must read for anyone who wants to think about these issues.

The use of XML for dynamic web pages is only a *very small part* and
recent part of the
XML universe. Bourret addresses the issue of data that is data-centric (and
easily represented in a database) vs document centric which tends to have
less structure and often more varied and unpredictable stucture. Think
about the difference between the structure of an address database and a
book.

A book may have a very complex, varied, repeatable nested hierarchical
structure that is very difficult to represent in a relational database.
Especially because the next book that comes along may have a different
structure. The building of a database schema for such a document is very
complex and once a data model in a database is created it is
more difficult to alter to accommodate slightly different
structured data.

DTDs  and XML Schemas can represent those data models more flexibly and
easily. And do not require fundamental reworking of the existing data
should there be additional structural modification.

On the other hand, an addressbook has a highly regular and predictable
structure that can be modeled once in a relational database. The utility
of XML is less evident in this case - although it can be useful as a
transport between two representations of the data.

So the answer is it depends on what your data is or "wants to be".

There's lots more to unpack but Bourret does it effectively and I will let
him provide further explanation.



Liz Shaw
Visiting Lecturer
Room 626 IS Building
Department of Library and Information Sciences
School of Information Science
University of Pittsburgh
Pittsburgh, PA 15260
Phone: (412)624-9455
Fax: (412)648-7001


On Thu, 7 Feb 2002, A. Bullen wrote:

> Dear all,
>
> At the urging of Roy Tennant, I am asking you all the same question that
> I asked him.
>
> Please pardon a rather naive question. I am a database programmer; that
> is, I put library SQL/ODBC connected databases on Internet-accesible
> platforms and build Web interfaces to them using Perl and Java. I have,
> of course, heard a great deal about XML and the revolution in
> information presentation. My question to use is: why do I need to work
> in XML when I can do everything in a sense better by using a database? I
> can replace XSLT/DTDs etc. with server side includes that detect browser
> types, and present the screen to the client accordingly by having a
> series of if/then statements in my presentation code. In short, I can
> build dynamically presented pages 'til the cows come home. What am I
> missing?
>
> I appreciate any comments or thoughts you might have on my dilemna.
>
> Sincerely,
> Andrew Bullen
> Illinois State Library
>
>



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