Hi Samuel,
you could use the layer filter, couldn't you? It's the second last
parameter in the setDataSource method.
Bernhard
Am 26.05.2016 um 12:23 schrieb Samuel Ingarfield:
Good idea, but I need to be able to vary a parameter in the sql expression
to filter the dataset differently as the user requires.
Filtering needs to happen on the sql server, the dataset is far too large
to filter directly within qgis (roughly 100mil rows).
Sam.
On Thu, May 26, 2016 at 4:20 PM, Bernhard Ströbl <[email protected]>
wrote:
Maybe it's easier to create a view on the DB and load that?
Bernhard
Am 26.05.2016 um 09:52 schrieb Samuel Ingarfield:
Hi Bernhard;
I can load the layer using an identical query in the DB manager sql
window.
Yes, r.id is a unique key.
Sam.
On Thu, May 26, 2016 at 3:37 PM, Bernhard Ströbl <
[email protected]>
wrote:
Can you load it via the "add PostGIS layer" button?
Is r.id a suitable key (unique)?
Bernhard
Am 26.05.2016 um 09:33 schrieb Samuel Ingarfield:
Hi All,
I'm trying to load a postigs layer via python which is defined by a very
long sql query. It seems that Qgis is truncating the query (which
obviously
causes it to fail). Has anyone come across this before and come up with
a
solution? Or am I loading the layer incorrectly?
There is an unanswered question on stackexchange regarding this:
http://gis.stackexchange.com/questions/162409/how-to-load-layers-from-postgres-using-select-statement
My python code is very simple:
sql = 'a very long query'
uri=QgsDataSourceURI()
uri.setConnection(host,"5432",dbname,user,passwd)
uri.setDataSource("",sql,"geom","","r.id")
vlayer = QgsVectorLayer(uri.uri(),"layer_name","postgres")
QgsMapLayerRegistry.instance().addMapLayer(vlayer)
The debug log shows the following:
qgsmessagelog.cpp(45) : (QgsMessageLog::logMessage) [1ms]
2016-05-26T15:16:14 PostGIS[1] NOTICE: NOTICE: identifier "...long
query
here..." will be truncated to "...truncated query here..."
qgsmessagelog.cpp(45) : (QgsMessageLog::logMessage) [1ms]
2016-05-26T15:16:14 PostGIS[1] Erroneous query: ...etc
Any help would be great.
Sam.
__________ Information from ESET Mail Security, version of virus signature
database 13547 (20160526) __________
The message was checked by ESET Mail Security.
http://www.eset.com
_______________________________________________
Qgis-user mailing list
[email protected]
List info: http://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-user
__________ Information from ESET Mail Security, version of virus signature
database 13548 (20160526) __________
The message was checked by ESET Mail Security.
http://www.eset.com
_______________________________________________
Qgis-user mailing list
[email protected]
List info: http://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-user
__________ Information from ESET Mail Security, version of virus signature
database 13548 (20160526) __________
The message was checked by ESET Mail Security.
http://www.eset.com
_______________________________________________
Qgis-user mailing list
[email protected]
List info: http://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-user
