[GRASS5] Postgresql and Grass

[John Huddleston]

Hi Eric (grass5 list)

----- Original Message -----
From: "Eric G . Miller" <egm2 at jps.net>
To: "grass5" <grass5 at geog.uni-hannover.de>
Sent: Friday, September 15, 2000 2:33 PM
Subject: Re: [GRASS5] Postgresql and Grass

> Is that a DTD or an XML Schema?  The new XML Schema standard looks like
> a better way than SGML/XML DTD's.  It has better typing and pattern
> matching constraints, to name a couple features.  These are the kinds of
> things needed for databases.  It's pretty new, so there aren't many
> tools to use it yet ;(
>
Xml Schema and DTD both were created .  Actually there are several
good tools available.  The one that meets my needs is Xml_Authority.  See
http://www.extensibility.com/

There are many major players in the industry who already use Xml as a
way of businees.  See http://www.xml.com/xml/pub/Guide/XML_Parsers
for those doing the parsers.

There are many sites including http://www.xmlsoftware.com/ which offer
support for those getting started.  For free software and tools see
http://www.garshol.priv.no/download/xmltools/  and the search tool
http://www.garshol.priv.no/cgi-bin/searchform.py and my favorite by Lars
http://www.garshol.priv.no/download/xmltools/

> Still, for any reasonably large database some kind of indexing scheme is
> necessary for performance.  Typing metadata is also desirable.  As a
> note: the preferred standard for XML is Unicode (get those high
> characters). I'm sure all our European friends would appreciate not
> limiting to ASCII.
>
As soon as I hit the send icon I knew I missed that.  Yes Unicode is the
standard for Xml.  Still portable, too.

List your priorities.  One is portability.  You want to be able to take
your datafile and use it on a different platform.  For our time series
data, netCDF ftp://ftp.unidata.ucar.edu/ files are the choice.   Xml is
useful for database schemas, transferring data, and more.  Performance
is good except when you add a large overhead with middleware.  We use
Xml in four different applications.  Two of them are large databases,
see http://nasis.nrcs.usda.gov/ for the US National Soils Information System
link.  Their plan is to put up one central web server for all to access.
Data will be served up in Xml format.

Let's see where we go with this.  I have tools, experience, and can guide
us down this path if we wish to go there.

John Huddleston


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