metadata development

On Fri, Mar 27, 2009 at 9:44 AM, Dara Olson <dolson@glifwc.org> wrote:

Happy spring.

I am new to postgres/postgis and am trying to figure out the best way to
approach documenting metadata within postgres.  Has there been anything
developed to add FGDC or Dublin Core standard metadata records into postgres
for each table within the database?  Is there any program that can access
postgres to insert metadata based on a standard or any other way to document
metadata for a postgres database?  Any help, suggestions or advice from
prior experiences would be greatly appreciated.

It's already defined within the database, both in the pg_xxx series of
tables and with the information_schema. Not sure what you need
besides that , as I'm not familiar with FGDC or Dublin Core standards.

On Fri, 2009-03-27 at 10:44 -0500, Dara Olson wrote:

I am new to postgres/postgis and am trying to figure out the best way
to approach documenting metadata within postgres. Has there been
anything developed to add FGDC or Dublin Core standard metadata
records into postgres for each table within the database? Is there
any program that can access postgres to insert metadata based on a
standard or any other way to document metadata for a postgres
database? Any help, suggestions or advice from prior experiences
would be greatly appreciated.

The only way we have of adding additional metadata onto an object is via
the COMMENT command, which accepts a text string as input.

You can fill that with metadata as much as you like - the system never
touches that information other than to store it. So you can put an XML
fragment with Dublin Core tags in there etc.

I think your suggestion that we should have a/another field to store
structured metadata about objects is a good one. It would certainly
encourage better documentation in-database. Perhaps as an additional XML
column.

--
Simon Riggs www.2ndQuadrant.com
PostgreSQL Training, Services and Support

Dara Olson wrote:

Happy spring.

I am new to postgres/postgis and am trying to figure out the best way
to approach documenting metadata within postgres. Has there been
anything developed to add FGDC or Dublin Core standard metadata
records into postgres for each table within the database? Is there
any program that can access postgres to insert metadata based on a
standard or any other way to document metadata for a postgres
database? Any help, suggestions or advice from prior experiences
would be greatly appreciated.

Thanks in advance.

Dara

I'm curious how this would be useful. Why would you want to associate
that sort of information with tables as metadata? Dublin core is a
metadata standard for "information resources" like documents (Tile,
Creator, Publisher, Author, Rights, etc), and FGDC is Geographic data. I
can easily imagine wanting to store such information in your database
using actual tables, as information about "entities" represented in your
database schema, but I don't think attaching it as metadata to a table
is really an appropriate solution. But I don't understand the scenario
you have in mind, and perhaps you could explain the scenario where this
makes sense.

I suspect you are reaching for database metadata simply because these
standards are often described as metadata; but these are usages of the
word "metadata" in very different contexts. What is called metadata in
many contexts is simply becomes data from the context of using a
relational database to represent it.

Eric

MG>(hopefully quick) comments below..

From: subscriber@blackbrook.org
CC: pgsql-general@postgresql.org
Subject: Re: [GENERAL] metadata development

Dara Olson wrote:

Happy spring.

MG>Happy Spring..

I am new to postgres/postgis and am trying to figure out the best way
to approach documenting metadata within postgres. Has there been
anything developed to add FGDC or Dublin Core standard metadata
records into postgres for each table within the database? Is there
any program that can access postgres to insert metadata based on a
standard or any other way to document metadata for a postgres
database? Any help, suggestions or advice from prior experiences
would be greatly appreciated.

Thanks in advance.

Dara

I'm curious how this would be useful. Why would you want to associate
that sort of information with tables as metadata? Dublin core is a
metadata standard for "information resources" like documents (Tile,
Creator, Publisher, Author, Rights, etc), and FGDC is Geographic data. I

MG>In that case you would want to look at PostGIS which will create/geo-encode/address-MG>decode GIS Spatial entities contained within polygon/sphere/circle
MG>http://postgis.refractions.net
MG>As the postgis library covers volumes of information please feel free to email me offline

can easily imagine wanting to store such information in your database
using actual tables, as information about "entities" represented in your
database schema, but I don't think attaching it as metadata to a table
is really an appropriate solution. But I don't understand the scenario
you have in mind, and perhaps you could explain the scenario where this
makes sense.

MG>Thus the reason for accessing Database information schema
MG>http://www.alberton.info/postgresql_meta_info.html

I suspect you are reaching for database metadata simply because these
standards are often described as metadata; but these are usages of the
word "metadata" in very different contexts. What is called metadata in
many contexts is simply becomes data from the context of using a
relational database to represent it.

MG>metadata means the Data which represents the structure of the referring entity
MG>in a PostGIS system metadata would be SpatialID, ESRI codes and so forth
MG>In a document centric system you would need to understand Templates,Formats
MG>and or stylesheets (to apply to a renderer to produce the document)
MG>In a Secure Enterprise System a document might require specific permissions
MG>such as what a Clinical Investigator might require for a drug study
MG>An example of a comprehensive secure enterprise system please refer to
MG>http://www.oracle.com/industries/life_sciences/oracle-clinical.html

Eric

MG>Martin

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