Let me take issue with one point (most of the rest I'm uninformed about):
Relational databases aren't particularly compact. What they are is
generalizable...and even there...
The most general compact database is a directed graph. Unfortunately,
writing queries for retrieval requires domain knowledge, and so does
designing the db files. A directed graph db is (or rather can be) also
more compact than a relational db.
The reason that relational databases won out was because it was easy to
standardize them. Prior to them, most dbs were hierarchical. This was
also more efficient than relational databases, but was less flexible.
The net databases existed, but were more difficult to use.
My suspicion is that we've evolved to use some form of net db storage.
Probably one that's equivalent to a partial directed graph (i.e., some,
but not all, node links are bidirectional). This is probably the most
efficient form that we know of. It's also a quite difficult one to
learn. But some problems can't be adequately represented by anything
else. (N.B.: It's possible to build a net db within a relational
db...but the overhead will kill you. It's also possible to build a
relational db within a net db, but sticking the normal form discipline
is nigh unto impossible. That's not the natural mode for a net db. So
the Relational db is probably the db analog of Turing complete...but
when presented with a problem that doesn't fit, it's also about as
efficient as a Turing machine. So this isn't an argument that you
REALLY can't use a relational db for all of your representations, but
rather that it's a really bad idea.)
Mark Waser wrote:
But how much information is in a map, and how much in the
relationship database? Presumably you can put some v. rough figures
on that for a given country or area. And the directions presumably
cover journeys on roads? Or walks in any direction and between any
spots too?
All of the information in the map is in the relational database
because the actual map is produced from the database (and information
doesn't appear from nowhere). Or, to be clearer, almost *any* map you
can buy today started life in a relational database. That's how the
US government stores it's maps. That's how virtually all modern map
printers store their maps because it's the most efficient way to store
map information.
The directions don't need to assume roads. They do so because that is
how cars travel. The same algorithms will handle hiking paths. Very
slightly different algorithms will handle off-road/off-path and will
even take into account elevation, streams, etc. -- so, to clearly
answer your question -- the modern map program can do everything that
you can do with a map (and even if it couldn't, the fact that the map
itself is produced solely from the database eliminates your original
query).
----- Original Message ----- From: "Mike Tintner"
<[EMAIL PROTECTED]>
To: <agi@v2.listbox.com>
Sent: Saturday, October 20, 2007 9:59 AM
Subject: Re: [agi] Human memory and number of synapses
MW:> Take your own example of "an outline map" -- *none* of the
current high-end
mapping services (MapQuest, Google Maps, etc) store their maps as
images. They *all* store them symbolicly in a relational database
because that is *the* most efficient way to store them so that they
can produce all of the different scale maps and directions that they
provide every day.
But how much information is in a map, and how much in the
relationship database? Presumably you can put some v. rough figures
on that for a given country or area. And the directions presumably
cover journeys on roads? Or walks in any direction and between any
spots too?
-----
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