Hugo Mercier wrote > Le 27/05/2014 15:03, Régis Haubourg a écrit : >> Hugo Mercier wrote >>> Or >>>> calculated fields in view can't be explicitly cast, so QGIS should have >>>> to >>>> guess data type based on a data scan (a major unadressed issue of >>>> sqlite) >>> >>> Hmmm I wasn't aware of this limitation in SQLITE views :( >> >> Yes, SQLITE does dynamic typing, so user or provider has to scan values >> to >> guess the right type. >> Here is a sqlite topic on that [0] >> And here my initial post in qgis list [1] >> >> [0] >> http://sqlite.1065341.n5.nabble.com/Computed-columns-in-VIEWs-return-NULL-but-should-be-able-to-be-typed-Any-ideas-td56769.html#a56770 >> >> [1] >> http://osgeo-org.1560.x6.nabble.com/Spatialite-can-t-type-fields-of-a-view-td5058436.html > > Hi, > Still on this topic. I made a few tests with sqlite views. > Indeed you cannot enforce a particular column type, but : > * you can convert values with CAST (casting 'foobar' to integer gives > 0), even if the resulting type is undefined > * QGIS does not seem to have any particular problem with untyped SQLite > columns, they will be reported as TEXT (QString) in the layer properties > * Even if the column is untyped, each value has its own type. So if a > column results from a CAST, to integer say, then the corresponding > attribute will be in a QVariant typed as an integer when it is fetched. > You can then use this value in a QgsExpression or a categorized > symbology as an integer. > > Am I missing other use cases where not having a column type is a problem ? > _______________________________________________ > Qgis-developer mailing list
> [email protected] > http://lists.osgeo.org/mailman/listinfo/qgis-developer Good news! I couldn't achieve that with views in QGIS 1.8, all field cast to numeric were converted in Qstrings. Régis -- View this message in context: http://osgeo-org.1560.x6.nabble.com/have-aggregate-window-expressions-ever-been-discussed-tp5142215p5142949.html Sent from the Quantum GIS - Developer mailing list archive at Nabble.com. _______________________________________________ Qgis-developer mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/qgis-developer
