xml-dev - Re: need for defining standard APIs for xml storage

[Dongwook Shin <dwshin@nlm.nih.gov>]

Hi,

Didier said:

> What we have in our hands is objects having particular interfaces. All
> objects inherit from the same base interface and thus we can say that all
> objects inherit form the same base class: the node. Then further value is
> added by augmenting new interfaces to the basic interface. This is the
> inheritance mechanism. Just take the case of an SVG element which adds a lot
> more value to the basic node interface. Now, let's say that these objects
> are simply an API used to access elements stored in a permanent information
> set (i.e. a grove). In this case, we deal with object nodes and therefore we
> can use some patterns like the observer or other pattern used to navigate in
> the whole tree or we can provide a member to access any element. This is
> what's behind the SelectNodes function. Whatever the object you obtained
> from the permanent information set, you can obtain a new one with this
> function. This without having to permanently keep a root object. You do not
> even have to get the notion of a document. Just the notion of an entry
> point. Also, this removes the dependency to the document object which in the
> case of a permanent information set does not make sense if the information
> set has been composed of several XML text documents. However, if the confort
> level of this abstraction is acceptable then we can perceive the whole
> library as a single document. However, I agree that we have to be very
> careful with our metaphors.

I think we converge into the same argument. Your suggestion for "SelectNodes"
seems a kind of indexing in my terminology. (I hope so :-)).
The main concern is if we do something more (for instance indexing) for
the efficient query evaluation in addition to DOM itself. If your
SelectNodes function does some, it is close to the notion of indexing.
Otherwise, it seems inevitable to search the whole document space
against the query "find the SPEECH having 'sword, love'" even with
SelectNodes function (I mean SelectNodes function should do at
run time).
Thanks.

Dongwook

--
Dongwook Shin
Visiting Scholar
Lister Hill National Center for Biomedical Communications
National Library of Medicine,
8600 Rockville Pike Bethesda 20894, MD
E-mail: dwshin@nlm.nih.gov
Tel: (301) 435-3257
FAX: (301) 480-3035
URL: http://dlb2.nlm.nih.gov/~dwshin



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