On Sat, Apr 12, 2014 at 5:10 PM, Anthony F <[email protected]> wrote:
> In the Query api, I can specify a subset of columns that I would like
> returned as part of my query. It would be useful if I could pass in a list
> of transform definitions or expressions and have the underlying database
> execute the transformations. This would be similar to a SQL projection
> such as
>
> 'select concat('id', 'name') as newname, buffer(the_geom, 0.1) as bufgeom
> from mygeomtable where within(the_geom, polygonWKT)'
>
> Is there a simple way to do this sort of thing that I have overlooked?
> I've been digging around in the Query api and the Transform process code to
> see if this is possible. I need a way to send the list of transform
> definitions to the underlying DataStore (in this case GeoMesa) so that it
> can execute the transformation in an optimal way. In the GeoMesa case, we
> would be able to leverage distributed parallel processing to compute an
> computationally expensive transformation.
>
In the case of the relational databases, we have a custom API that allows
to define "virtual tables", where you really
just provide the sql to be run, and the store will use it as a source of
records (and will wrap it in a larger query by
stashing it as a subquery in the from clause).
It's then up to the application to recognize that specific extension, for
example GeoServer has custom code targetting
the JDBCDataStore family.
But no, there is no general mechanism.
Cheers
Andrea
--
==
Meet us at GEO Business 2014! in London! Visit http://goo.gl/fES3aK
for more information.
==
Ing. Andrea Aime
@geowolf
Technical Lead
GeoSolutions S.A.S.
Via Poggio alle Viti 1187
55054 Massarosa (LU)
Italy
phone: +39 0584 962313
fax: +39 0584 1660272
mob: +39 339 8844549
http://www.geo-solutions.it
http://twitter.com/geosolutions_it
-------------------------------------------------------
------------------------------------------------------------------------------
Put Bad Developers to Shame
Dominate Development with Jenkins Continuous Integration
Continuously Automate Build, Test & Deployment
Start a new project now. Try Jenkins in the cloud.
http://p.sf.net/sfu/13600_Cloudbees
_______________________________________________
GeoTools-Devel mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/geotools-devel
