Re: [udig-devel] Reference for table join

[andrea antonello <andrea.antonello@xxxxxxxxx>]

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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