On Sat, Oct 27, 2012 at 2:46 PM, Matthias Kuhn <[email protected]> wrote: > > Sounds like something worth considering. > Something else I have been thinking of and what would increase > performance pretty good in some situations would be to be able to select > by an expression: > > myFeatureSet = provider.select( QgsExpression( 'attr1 = 1 AND attr2 > 5' > ) ) > while myFeatureSet.nextFeature(myFeature): > do interesting stuff...
Yes, this is another feature I have in my mind, something that could be later added to QgsFeatureRequest. Actually for expressions there are two choices: expressions for QgsExpression and provider's native expressions (e.g. SQL supported by PostGIS). The difference is that the former ones should work for any provider, while the latter ones only for those with some native expression language - those are likely to be faster since the expression would be executed in the backend, so less data transfer and thus faster fetching. Martin _______________________________________________ Qgis-developer mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/qgis-developer
