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Re: [xml-dev] XML Database Decision Tree?

"Champion, Mike" wrote:
> > -----Original Message-----
> > From: Leigh Dodds [mailto:ldodds@ingenta.com]
> > Sent: Thursday, October 18, 2001 11:16 AM
> > To: Champion, Mike; xml-dev@lists.xml.org
> > Subject: RE: [xml-dev] XML Database Decision Tree?
> >
> >
> > E.g. if your schema is in a constant state of change (and
> > they probably all are over time) or has yet to be finalized/standardised
> then
> > locking it into a database structure might be unwise.
> > Or am I off track on that one?
> You're right.  Speaking generally, the native XML DBMS tend to be more
> flexible in handling data with no schema, or with evolving schema, than
> solutions based on normalizing XML into RDBMS tables.

Could you explain this further? The flexibility is easy to understand,
but I'm having trouble seeing what it buys me. If I store my data 17
different ways, I'm going to have one heck of a time querying it. This
is the whole point of having a single schema.

As it has been explained to me, the main advantage comes at design time,
since developers can store documents that conform to any schema they
want, immediately, without having to approve schema changes through the
DBA. This advantage is political, not technical, and will go away if
native XML databases are successful enough that DBAs start trying to
administer them and the schemas that apply to them.

Furthermore, I thought one of the functions of the DBA was to act as a
mediator (roadblock?) between different groups who want to access the
same data and who both want to modify the same schema, thereby breaking
each others' applications. Doing an end run around this may yield short
term gains, but will be disastrous in the long run.

So what am I missing? I suspect this is one argument that I'm going to
have to be bludgeoned with repeatedly before I understand it.

-- Ron