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On Wed, 27 Aug 2003, Thomas B. Passin wrote:
> Just sloppy language on my part, I know that "relational" does not mean a
> storage format. I did not really mean storage of bytes, but was thinking of
> the logical (or conceptual, if you like) level.
> For example, it is easy to model a two-level hierarchy in SQL, but it is
> awkward to model (and query) a hierarchy of an indefinite number of levels.
> So when the data model is deeply hierarchical, xml structures might have an
When you are thinking in terms of these, I think you should definitely see
some of the best practices for hierarchical model. For example, look up
any of the editions of
"Fundamentals of Database Systems" by Elmasri/Navathe
Jonathan Robie has worked on non-relational stores for XML, hopefully he
can give a non-salesperson and convincing perspective, as to when
non-relational store performs better than using relational stores..
note: relational store: storage model used for relational DBs..
cheers and regards - murali.
> If the data model is sparse, xml may be much better than a table-like model.
> Similarly when the contents of an element type may vary quite bit from one
> instance to another.
> On the other hand, if you create a well-normalized data model to begin
> with - when that is practical - you could probably implement it either with
> xml or with a relational database. What are the differentiators between
> going one way or the other?