On 07.11.2014 17:25, Andreas Neumann wrote: > Hi, > > What you probably ask for are database triggers combined with storage. > This is not what virtual fields are for. If they were stored - they > wouldn't be called virtual ;-)
we could still add materialized virtual fields :-) > > You can do that f.e. with Postgis. With shapefiles not. However, if > you share the project with the other PC, the virtual fields work fine. ... or use layer -> save as before sharing it. That will make a permanent copy of the values at the time of saving. Matthias > > Andreas > > On 07.11.2014 17:21, Zoltan Szecsei wrote: >> Hi Matthias, >> Thanks for the quick answer. >> The virtual field acts just like I want it to, except that it does >> not permanently store the column in the attribute table. >> I tried getting clever by then adding a second 'Field Calculation' to >> update the existing 'Sheet' field from the virtual field, but that >> won't do it either. >> >> So, for me there are two shortcomings: >> >> 1. To be able to store and recall the 'Expression' and not lose it >> after closing the Field Calculator >> 2. To be able to add the virtual fields that you create, into the >> attribute table. >> 3. (And then of course to re-open the Shape file on another PC and >> have these Field Calculations still functional) >> >> Any further possibilities I can try? >> >> Regards & thanks again, >> Zoltan >> >> >> On 2014/11/07 18:01, Matthias Kuhn wrote: >>> Hi Zoltan, >>> >>> Since QGIS 2.6 this possibility exists. It is called "Virtual Field". >>> You must not create the attribute when creating the shapefile. Just open >>> the field calculator, create a new field in there and check the "virtual >>> field" checkbox. >>> >>> Regards, >>> Matthias >>> >>> On 07.11.2014 16:54, Zoltan Szecsei wrote: >>>> Hi, >>>> I'm using QGIS 2.6.0 on Win 7 x64 - installed via OSGEO4w >>>> >>>> Is there a way to store your field calculator expression to always >>>> process and update that specific field, should geometry be edited or >>>> created for that Layer? >>>> >>>> Let's say I want to create a blank POINT shape file, with a text >>>> attribute called "Sheet". >>>> Whenever a POINT is created or moved, I want this field to be >>>> dynamically updated with: >>>> >>>> tostring(abs(toint($y)))+tostring(abs(toint($x))) >>>> >>>> For testing thus far have: >>>> >>>> * created 2 points >>>> * Opened the field calculator, clicked 'Update Existing Field' and >>>> put in the expression. >>>> * The two existing points now have the correct TEXT values in the >>>> Sheet field >>>> * I close the Field calculator >>>> * Create a new point in my layer >>>> * open the attribute table to find that the 'Sheet' field for this >>>> new point is blank >>>> * I open the Field Calculator and I cannot even find a way to call >>>> back the previous expression I used. >>>> >>>> >>>> Am I using the correct QGIS functionality to achieve what I need to, >>>> and if so, where am I going wrong? >>>> >>>> Thanks & regards, >>>> Zoltan >>>> >>>> >>>> -- >>>> >>>> =========================================== >>>> Zoltan Szecsei PrGISc [PGP0031] >>>> Geograph (Pty) Ltd. >>>> GIS and Photogrammetric Services >>>> >>>> P.O. Box 7, Muizenberg 7950, South Africa. >>>> >>>> Mobile: +27-83-6004028 >>>> Fax: +27-86-6115323 www.geograph.co.za >>>> =========================================== >>>> >>>> >>>> _______________________________________________ >>>> Qgis-developer mailing list >>>> [email protected] >>>> http://lists.osgeo.org/mailman/listinfo/qgis-developer >> >> >> -- >> >> =========================================== >> Zoltan Szecsei PrGISc [PGP0031] >> Geograph (Pty) Ltd. >> GIS and Photogrammetric Services >> >> P.O. Box 7, Muizenberg 7950, South Africa. >> >> Mobile: +27-83-6004028 >> Fax: +27-86-6115323 www.geograph.co.za >> =========================================== >> >> >> _______________________________________________ >> Qgis-developer mailing list >> [email protected] >> http://lists.osgeo.org/mailman/listinfo/qgis-developer > > > > _______________________________________________ > Qgis-developer mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/qgis-developer -- Help getting QGIS to the next level of quality before November 15! http://blog.vitu.ch/10102014-1046/crowdfunding-initiative-automated-testing _______________________________________________ Qgis-developer mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/qgis-developer
