[Qgis-developer] Visualisation of relations

[Matthias Kuhn]

Hi Patrick,

for the side that contains the foreign key, there is the "relation
reference" widget which has a configuration option "show embedded form"
(I haven't used it in years and a quick check on it didn't work, so
maybe it needs fixing).

Agreed, collapsed by default makes sense for huge models. For small ones
it's a bit strange though. Another approach would be to put them on
separate tabs by default, I think that could look quite nice also. What
do you think?

Regards
Matthias

On 10/31/2016 09:54 AM, Patrick Valsecchi wrote:
> Hi Matthias,
> 
> My screenshot shows only 1:N links. N:1 links are not supported. By N:1,
> I mean the relations from the side that contains the foreign key. If I
> open the form for the "appart" layer, it doesn't show the linked "maison".
> 
> Yes, the collapsed state is remembered, but the default should be
> collapsed. If the default is to open everything, the GUI is going to
> explode if we have hundreds of linked tables.
> 
> Thanks and CU.
> 
> On Sun, Oct 16, 2016 at 8:57 AM, Matthias Kuhn <matthias at opengis.ch
> <mailto:matthias at opengis.ch>> wrote:
> 
>     Hi Patrick,
> 
>     Making forms and relations more usable is always welcome.
> 
>     What exactly are the problems you have with the current solution?
>     I see that you mentioned the lack of the N:1 side which is available
>     including add feature, add link, remove feature, remove link pretty much
>     the way you describe it. On [1] there is some explanation I wrote on the
>     first implementation.
> 
>     I think you should have found that since it's shown on the screenshot
>     which is attached to your mail.
> 
>     Also lazy loading (load when first visible) was introduced once for
>     performance reasons and the collapsed state of the group boxes
>     containing the QgsRelationEditor widget is remembered.
> 
>     So I think that functionality-wise, most of it should be there already.
>     With a lot of air left for improvement on the usability side.
> 
>     Cheers
>     Matthias
> 
>     [1] http://blog.vitu.ch/10112013-1201/qgis-relations
>     <http://blog.vitu.ch/10112013-1201/qgis-relations>
> 
> 
>     On 10/07/2016 09:27 AM, Patrick Valsecchi wrote:
>     > Hi,
>     >
>     > I'm tasked with making QGIS a bit more usable with complex database
>     > schemas having a lot of relations (up to hundreds of linked tables). The
>     > INSPIRE people were a bit too inspired when creating their data schemas
>     > and now we have to try to make QGIS able to cope with that.
>     >
>     > My concerns with the current situation (as of QGIS master) are:
>     >
>     >   * We can specify the relations between the layers at the project
>     level
>     >     (it's now easier with the auto-discover feature for PostGIS and
>     >     Spatialite). But those are only showing in the QgsAttributeForm for
>     >     the 1-N side (the side that doesn't have the foreign key). Why not
>     >     on the N-1 side?
>     >   * For showing the N-1 side in the QgsAttributeForm, one can define a
>     >     Join in the layer's properties, but I don't see the point of having
>     >     to define it here as well when we have already the relations info at
>     >     the project level. I see a use for special joins, but for relations,
>     >     I don't see why we have to define it twice. And the way it's
>     >     displayed is not allowing to create joins or edit the joined fields.
>     >   * I let you imagine the look of the feature attribute form when
>     there
>     >     are hundreds of directly and indirectly linked tabled. This is just
>     >     not usable if we display all of them directly like that. Just look
>     >     at the attached screen shot that shows what happens by default with
>     >     only 3 tables. It's already a mess.
>     >
>     > Now, what I propose is:
>     >
>     >   * Not expand the relation widget (QgsCollapsibleGroupBox) by default
>     >     and build it's content only when it is expanded the first time
>     >     (think of what would happen when you have loops in the schema).
>     >   * Show N-1 relations as well, in a collapsed by default
>     >     QgsCollapsibleGroupBox, including a way to add a new linked entry,
>     >     remove the link (put the FK to NULL) and delete it.
>     >   * Add a button to open a related feature in a new window.
>     >
>     > What do you guys think?
>     >
>     > Thanks.
>     >
>     >
>     >
>     > _______________________________________________
>     > Qgis-developer mailing list
>     > Qgis-developer at lists.osgeo.org <mailto:Qgis-developer at lists.osgeo.org>
>     > List info: http://lists.osgeo.org/mailman/listinfo/qgis-developer
>     <http://lists.osgeo.org/mailman/listinfo/qgis-developer>
>     > Unsubscribe:
>     http://lists.osgeo.org/mailman/listinfo/qgis-developer
>     <http://lists.osgeo.org/mailman/listinfo/qgis-developer>
>     >
>     _______________________________________________
>     Qgis-developer mailing list
>     Qgis-developer at lists.osgeo.org <mailto:Qgis-developer at lists.osgeo.org>
>     List info: http://lists.osgeo.org/mailman/listinfo/qgis-developer
>     <http://lists.osgeo.org/mailman/listinfo/qgis-developer>
>     Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-developer
>     <http://lists.osgeo.org/mailman/listinfo/qgis-developer>
> 
>