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   RE: [xml-dev] XML and the Relational Model (was Re: [xml-dev] A standa

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> (b) XML also allows us various ways of representing relationships: like
> parent-child, IDREF, or foreign keys. Each representation might be
> "convenient" for the user for different applications..

This is the key advantage of using XML to view data: many relationships can
naturally be described hierarchically. Or, at least, we as humans see such
hierarchies as natural.

Relational purists will say tables and rows can represent such hierarchies,
and do so in more flexible manner with better integrity. Fab Pascal, in his
"Practical Issues in Database Management" book, chapter 7, gives an example.

The problem is that he needs a diagram to illustrate the heirarchial
relationships between table rows, because the hierarchy is far from obvious
when looking at the table rows alone.  He could have just as well, instead
of a diagram, used XML elements; it would have been just a clear.  ;-D

> (c) As someone mentioned before, try for a federated DB to use relational
> as the unified view of the different sources, it gets so difficult to do
> so, because relational does not give us flexibility...
> XML might give some more flexibility needed for our application..
> (d) Consider the case where data stored in our DB includes structured
> portion as well as semi-structured (text) portion.. for example, for each
> employee, you store attributes like his DofB, salary etc, and also, we
> have a column where we want a description of the person, which could be in
> XML..
> I hope there are applications which require (d)..
> best regards - murali.
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