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On 7/20/05, Ronald Bourret <rpbourret@rpbourret.com> wrote:
> Peter Hunsberger wrote:
> > On 7/19/05, Ronald Bourret <rpbourret@rpbourret.com> wrote:
> >
> >>Will the addition of XML data types to relational databases help this
> >>problem, at least for data-centric schemas? It's a bit of an force-fit,
> >>but it seems that mixed content could be mapped to and accessed from an
> >>XML column when the meaning of that content is a single word, even an
> >>annotated one.
> >
> > If you're indexing in any way (walking a Blob or shredding) then you
> > need some form of schema support...
>
> Actually, virtually all native XML databases can index arbitrary XML. In
> some cases, this is inherent in the internal structure of the database.
> For example, NeoCore stores data in hash tables of the paths to that
> data. Thus, the index and the data storage are the same. In other cases,
> databases create more conventional indexes (such as B-trees) as
> necessary, rather than simply in response to a create index command.
> Whether this is always done or the user has the choice to limit what is
> indexed depends on the database.
>
I didn't phrase that very well; what I meant was that in order to know
what element you're putting where in the database you need to have
some form of schema support. Eg, you need to know that X and Y are
base elements and Z is an annotation that can be contained in or
attached to either. I agree that the physical index itself is
business as usual...
<snip/>
--
Peter Hunsberger
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