[Qgis-developer] Updating field with a trigger

[Yves Jacolin]

On Thursday, September 10, 2015 9:36:31 Bernhard Ströbl wrote:
> Hi Yves,
> 
> Am 10.09.2015 um 09:27 schrieb Yves Jacolin:
>[..]
> > 
> >> Apart from that if
> >> field#2 = field#1 + x
> >> then field#2 is totally redundant. You could either create a view
> >> containing this field or create a virtual field in QGIS.
> > 
> > I just simplified for the test case. This is more complicated but was not
> > useful to give such details ;)
> 
> still this should be considered an option to show the resulting value to
> the user instead of having it in a field of its own.

Humm, I need to think a little bit on this. I am not sure that move some logic 
from the db to QGIS is always a good things. 

One of the use case which lead me to let this logic in the DB is when I use 
this field in several part (for example, in a layer in QGIS and in a website, 
for an export with ogr2ogr or event in several layers in QGIS). 

It is easier to manage one location (ie the trigger) than several (in QGIS if 
we use this field in different layer). I need to check this but we are in such 
use case.

Anyway, I agree with you in other use case that it is easier to manage this as 
a virtual field, much less trouble :)

Y.