Re: R-Trees.

I don't think this is a postgres question it is perl one ,so you are in
the wrong place .just as a hint
look for a perl module that do what you want *i think perl::Text os
something).Any way this is a
wrong list .
Evgeny
Michael Wray wrote:

>(Please CC me, if you reply as I am out of pocket now and not able to be on
>mailing lists at this time...);
>
>I'm not sure which list I was reading, but I've been looking for info about
>R-Trees, and stumbled across my favourite DB backend's mailing lists...
>
>I've used RTREE based db engines before (Informix) but was unaware of PostGres
>and MySQL implementing RTREE capability until tonight.
>
>While I understand the basic concept of an RTREE. I would like to be pointed
>someplace to get more info on the algorithms of RTREES and how they work, as
>I'd like to implement something that uses RTREE algorithms, and be able to
>represent a whole record w/ items with values,subvalues,subsubvalues,
>etc...in an object type format.
>
>(Something that can get a whole record for a customer and break it out into
>all the pieces automagically.. as an example.)
>
>
>I'm used to doing code like this for parsing data for a customer from an
>RTREE:
>(Mixed Pseudocode and perl):
>$customer=GETDATA;
>$MultivalueMarker="~";
>$SubvalueMarker=0007;
>$valuemarker=0008;
>
>foreach $customer (@recordlist) {
> @carray=split ($ValueMarker,$customer,10);
> @phonearray=split($SubValueMarker,@carray[7]);
> foreach $phoneitem (@phonearray) {
> my ($phone,$number)= split($MultiValueMarker,$phoneitem);
> $phonehash{$phone}=$number;
> }
> @domainarray=split ($SubValueMarker,@carray[8]);
> @emailarray=split ($MultiValueMarker,@domainarray[2]);
>
>}
>
>And at some point the data is packed and unpacked....
>I'd like to hide all that using objects and make it so one could say read in a
>template, and then make access to the data based on names defined in the
>template.
>
>As for an SQL database using Rtrees:
>This doesn't seem like good practice for use if one is using SQL to do queries
>with as it isn't structured around this kind of datatype, is there black
>magic going on here that autoguesses joins, etc based on relationship of data
>in the tree?
>
>(When PG first announced Multidimensional support for the db, I didn't believe
>it to be an rtree because of the slowness at which queries occurred, when
>using multivalued data, even in a small database.) I would hope that pgsql
>would have other ways of handling queries on an rtree. And it may well do
>that now.)
>
>
>
>
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