Depends on your update/select ratio. If you have lots of SELECT like 90% and few updates and your just serving your data lets say to mapserver I would just go with 2 geometry columns iit's easier and faster.
On Tue, Sep 1, 2009 at 6:39 PM, <[email protected]> wrote: > > Thanks Pavel for your answer. > Do you suggest that I could use one geometry column and create several index > instead? > > Steve Toutant, M. Sc. > Analyste en géomatique > Secteur environnement > Direction des risques biologiques, environnementaux et occupationnels > Institut national de santé publique du Québec > 945, avenue Wolfe > Québec, Qc G1V 5B3 > > Tél.: (418) 650-5115 #5281 > Fax.: (418) 654-3144 > [email protected] > http://www.inspq.qc.ca > > > > > Pavel Iacovlev <[email protected]>@postgis.refractions.net > Envoyé par : [email protected] > > 01/09/2009 11:34 AM > > Veuillez répondre à > PostGIS Users Discussion <[email protected]> > A > PostGIS Users Discussion <[email protected]> > cc > Objet > Re: [postgis-users] several SRID on one table > > > > > > > The cons I think are that some 3rd party apps may get confused then > working with PostGIS as they expect 1 geometry column per table, old > version of QGIS have this problem (I may be wrong). > > In general you should have NO trouble with dual geometry columns in > your app, I use this approach in production and it works fine and it's > easy to implement. > > As a note you can create an INDEX on a geometry column that is a > transformed geometry to specified projection and you should get really > fast geometry on the fly projection transformation. > CREATE INDEX myindex ON mytable USING GIST ( ST_Transform(the_geom, mysrid) > ); > Don't forget to run EXPLAINS to see if it actually works. > > On Tue, Sep 1, 2009 at 5:46 PM, <[email protected]> wrote: >> >> Hello, >> We need to use a table for several purposes with different SRID. >> Is it a good practice to have several geometry columns on one table or >> should we create one table per SRID? >> What are the pros and cons of using several geometry columns on one table? >> >> thanks >> Steve >> >> Steve Toutant, M. Sc. >> Analyste en géomatique >> Secteur environnement >> Direction des risques biologiques, environnementaux et occupationnels >> Institut national de santé publique du Québec >> 945, avenue Wolfe >> Québec, Qc G1V 5B3 >> >> Tél.: (418) 650-5115 #5281 >> Fax.: (418) 654-3144 >> [email protected] >> http://www.inspq.qc.ca >> >> >> >> _______________________________________________ >> postgis-users mailing list >> [email protected] >> http://postgis.refractions.net/mailman/listinfo/postgis-users >> >> > > > > -- > http://iap.md, The future is open > _______________________________________________ > postgis-users mailing list > [email protected] > http://postgis.refractions.net/mailman/listinfo/postgis-users > > > > > _______________________________________________ > postgis-users mailing list > [email protected] > http://postgis.refractions.net/mailman/listinfo/postgis-users > > -- http://iap.md, The future is open _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
