Landon Blake wrote:
Thanks for that response Frank. I find this very interesting.
It seems that you could model just about any data stored in a RDBMS as
an object in an object-oriented programming language.
For example: If you were writing a database program for used car lots
you could represent cars as objects instead of data in individual table
cells. But at some point you have to ask, is this worth the effort? I
think that is one advantage of the RDBMS model, you can represent all
types of data without custom programming.
Landon,
I did not in any way suggest that the solution to the fully normalized
RDBMS model is an object oriented database. Only that for reasonable
performance it is desirable to "closely associate" the whole geometry
of a feature with the feature record, and have some sort of spatial
extents information for features that allows reasonable fast spatial
queries.
Still, I wonder if the overhead of an additional engine on top of the
database makes the speed gap small. Have there been any documented
benchmarks that compare this model to others?
I think I'll see if my friend is interested in running some tests.
I would encourage him to do some comparisons. For instance, try loading
a "counties worth" of TIGER data in fully normalized form, and in WKB+extents
form and then do various operations. For instance, see how long it takes
to fetch all the features and their geometries that match some non
spatial criteria (perhaps a single zip code). And see how long it takes
to fetch all the features and their geometries that meet a particular
spatial criteria (perhaps intersecting a 1mile x 1mile rectangle).
Here I'm not even suggesting any special spatial type or specially
optimized spatial index ... that's just gravy on the cake.
Best regards,
--
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up | Frank Warmerdam, [EMAIL PROTECTED]
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush | President OSGeo, http://osgeo.org
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