Performance improvement for xml loads (+comments)

[Derek Atkins]

Christopher Browne <cbbrowne@hex.net> writes:

> XML has the merit of being easily serialized; it wouldn't be too
> difficult to use it for THAT purpose, and using other formats that are
> isomorphic to it for more direct access.

Lots of formats can be easily serialized.  So can ASN.1.  So can
XDR.  That's not a unique feature of XML.

> One thought would be that the IronDoc object database system was
> designed with isomorphism with XML as one of the secondary goals. [See
> <http://www.ntlug.org/~cbbrowne/oodbms.html> for linkage to IronDoc
> info; it's vaporware, but characteristic of the sort of DB that might be
> appropriate...]

According to the IronDoc docs you "can consider IronDoc a binary
compiled fornat(sic) [for XML]" which implies to me that it would have
the same extensibility problems that XDR would have.  In other words,
if you change the data structures you not only need to recompile but
you need to keep the old data structures around in order to read older
data formats.  This also has the side-effect that if you change the
data structures, a parser for the older structures wont be able to
read the newer structures.

I think that the only data object description language that solves
this particular problem is ASN.1, but even ASN.1 can leave pitfalls in
object definitions (where extending an object leads to
incompatibilities in the same way that it would here).  So, you don't
win anything with ASN.1 (except object bloat due to self-describing
objects).

> I don't think this is the right answer; the "semi-automatic" part causes
> me concern, in that it doesn't guarantee extensibility.

Again, can you please define what you mean by "guarantee
extensibility"?  I'd like to see exactly what the extensibility
requirements are, because I certainly don't feel that I understand
what they are.  I just want to make sure that collectively we do all
understand them (or at least we're all on the same page as to what is
meant by the term).

-derek

-- 
       Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
       Member, MIT Student Information Processing Board  (SIPB)
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