Re: [udig-devel] Reference for table join

[Jody Garnett <jody.garnett@xxxxxxxxx>]

You have the same understanding as me; but perhaps your customers are
more talented in their use of PostGIS.
My most common use is joining a shapefile to a CSV file storing
additional information about the shapes (also using a common id as you
indicated).

So for me the "postgis on postgis" join is a special case that would
be great to nail using an SQL statement.

Jody

On Fri, Nov 12, 2010 at 6:10 PM, andrea antonello
<andrea.antonello@xxxxxxxxx> wrote:
> Hi Jody,
> it might be a language barrier problem of mine, but I do not
> understand exactly what you write.
>
> To me table join is for example linking two tables by a common
> attribute. The most common case, which has also been asked dozens of
> times in this list or by uDig users, is that of being able to joint
> two postgis tables Aspatial & Bnonspatial by a common field and for
> example view it as one (join) in the table view.
> This obviously would also introduce the possibility of multiplicity,
> i.e. there might be several records in Bnonspatial that link to a
> single record in Aspatial.
>
> Alright, would you mind to repeat your thought of the last email with
> this example in mind?
>
> Thanks man,
> Andrea
>
>
>
>
> On Fri, Nov 12, 2010 at 4:04 AM, Jody Garnett <jody.garnett@xxxxxxxxx> wrote:
>> Afternoon
>>
>> I have accomplished table joins (with the udig reshape operation) in
>> the past by defining a custom function ... the thought being:
>>
>> 1. function can load in the target csv file
>> 2. function can take the external key as an argument
>> 3. look up the correct row; and return the requested attributes
>> 4. as long as the taget file is cached in memory performance can go pretty well
>>
>> This has been used by the app schema team to some effect; for joining
>> property files etc...
>>
>> I had the following sent in my direction; and may serve as a reference
>> point if we want to look into a more serious solution.
>>
>> Jody
>>
>> ---------------------------------------
>> From: OGC Press <announce@xxxxxxxxxxxxxxxxxx>
>> Reply-To: <announce@xxxxxxxxxxx>, <announce@xxxxxxxxxxxxxxxxxx>
>> Date: Tue, 16 Mar 2010 10:53:31 +1000
>> To: <media@xxxxxxxxxxxxxxxxxxxxxxxx>
>> Subject: [OGC Press Release] OGC Seeks Comments on Table Joining
>> Service Standard
>>
>>
>> PRESS ANNOUNCEMENT FOR IMMEDIATE RELEASE
>> For information about this announcement, contact:
>>
>> Lance McKee
>> Outreach Consultant
>> Open Geospatial Consortium, Inc
>> tel: +1-508-655-5858
>> outreach@xxxxxxxxxxxxxxxxxx
>>
>> -----------------------------------------------------------------------
>>
>> Wayland, Mass., 15 March, 2010 - The Open Geospatial Consortium, Inc.
>> (OGC®) seeks public comment on the draft OGC Table Joining Service
>> (TJS) Interface Standard. This standard defines an interface for
>> services that provide the ability to join attribute data stored in one
>> database on a network with the corresponding geometry (points, lines,
>> or polygons) stored in another network accessible database.
>>
>> For example, a table on one server may indicate the population of
>> various cities, while a second server may contain the geometry that
>> describes the cities' locations and boundaries. The TJS standard
>> describes a set of interfaces for both servers that would allow the
>> city name to be used as the "common geographic identifier" in order to
>> join the population data to its geometry, thus enabling the user to
>> create a map or perform geospatial analysis on the tabular data. An
>> earlier draft of this specification was called the "Geographic Linkage
>> Service".
>>
>> The proposed OGC TJS 1.0 standard and information on submitting
>> comments on this document are available at
>> http://www.opengeospatial.org/standards/requests/62.  The
>> public comment period closes on 14 April, 2010.
>>
>> The OGC is an international consortium of more than 390 companies,
>> government agencies, research organizations, and universities
>> participating in a consensus process to develop publicly available
>> geospatial standards. OGC Standards support interoperable solutions
>> that "geo-enable" the Web, wireless and location-based services, and
>> mainstream IT. OGC Standards empower technology developers to make
>> geospatial information and services accessible and useful with any
>> application that needs to be geospatially enabled. Visit the OGC
>> website at http://www.opengeospatial.org.
>> _______________________________________________
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