Hi Yves,

Am 10.09.2015 um 09:27 schrieb Yves Jacolin:
Hello,

On Thursday, September 10, 2015 8:50:24 Bernhard Ströbl wrote:
Hi Yves,

I have only experience with PostgreSQL but I assume that sqlite behaves
similar. If you edit a feature in QGIS your layer is in edit mode
(allowing for undo/redo). Changes are committed only when you click on
the respective button. This results in an update statement sent to your
db which then calls your trigger. Thus field#2 is not changed when you
change #1 _in QGIS_. In order to have such behaviour AFAIK you would
have to do it in Python (which would be totally independent from the db
trigger then).
Thanks for confirmation.

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.


Thanks again Bernhard!

You're welcome

Bernhard


Y.

Am 09.09.2015 um 13:41 schrieb Yves Jacolin:
Hello,

I have a small project with a sqlite db. There is a layer with a trigger
on a field #1 to calculate an addition and put the result in another
field (#2).

When I edit the initial field #1, the second field #2 is not updated in
the
form. I need to close the form and open it again to see the result.

Do you think this is a known limitation or a bug?

My point of view is that it is a limitation, as QGIS don't know that a
trigger can change a value in the same feature server side.

I don't know if QGIS should or could get an update of the data server side
before display the form content.

In case there is no such plan, do you think we can add some logic in a
python script to force the form update (I can ask to Arnaud next week on
this topic).

Thanks,

Y.


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