Hi Nyall,
2016-12-27 2:03 GMT+01:00 Nyall Dawson <nyall.daw...@gmail.com>: > On 23 December 2016 at 23:37, Paolo Cavallini <cavall...@faunalia.it> > wrote: > > Il 23/12/2016 14:32, Giovanni Manghi ha scritto: > > > >> The solution from the Gitter discussion > >> > >> aggregate( 'layername','max',"id")+1 > > > > thanks Giovanni > > > >> We need of course a more user friendly way to allow users have > >> incremental/serial ids in their shapefiles... > > > > sure, e.g. a named preset expression, as previously suggested. > > all the best. > > In master you can add UNIQUE and NOT NULL constraints to the field > from within QGIS. This will cause QGIS to automatically populate it > with a serial type value whenever a new feature is created. > > How does this work? I thought to document this tip in the User manual and wanted to give it a try before but always fail: I created an integer field which is recognized in the Attribute Forms dialog as a range I checked "unique" and "not null" constraints (and unchecked "allow null values" from the range widget properties) The first created feature had value =0 The second one also got 0 with the yellow cross on the side But changes (with two 0 values) are saved in the layer. Enforcing the constraints do not help, neither do setting the widget as "Text Edit". Did I miss something (btw i'm using a temporary layer but also failed with shapefile) or is it broken. Any help is welcome. Thanks, Harrissou > Nyall > > > > -- > > Paolo Cavallini - www.faunalia.eu > > QGIS & PostGIS courses: http://www.faunalia.eu/training.html > > https://www.google.com/trends/explore?date=all&geo=IT&q=qgis,arcgis > > _______________________________________________ > > Qgis-developer mailing list > > Qgis-developer@lists.osgeo.org > > List info: http://lists.osgeo.org/mailman/listinfo/qgis-developer > > Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-developer > _______________________________________________ > Qgis-developer mailing list > Qgis-developer@lists.osgeo.org > List info: http://lists.osgeo.org/mailman/listinfo/qgis-developer > Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-developer >
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