[Qgis-user] Qgis, postgis and updateable views

[Ricardo Filipe Soares Garcia da]

Hi Rob and the rest of the list

Strangely enough, today I'm not experiencing the crash that motivated
my previous e-mail. Qgis is allowing me to create new geometries in my
postgis VIEW layer. The crash was being caused by some other factor
that I haven't been able to track down.

Now I'm getting another error when I try to save my changes, but it is
probably due to some error in my INSERT rule on postgreSQL's side, as
I didn't have time to test it properly.

Today I am busy with other issues but I will get back at it tomorrow
and will report my progress.

If you are interested I can try to make a detailed explanation showing
how to get the whole 'postgis editable views layers' working, when I
do manage to get them going that is ;)

As a side note, I have been experiencing apparently random crashes
that happen when I click on a layer in the 'Layers' dock window. I
don't know what is causing them... I'll try to nail it down and file a
ticket.

On Mon, Oct 26, 2009 at 12:13 PM, Rob Marjot <rob at marjot-multisoft.com> wrote:
> Hi Ricardo,
> I am planning to do sort of the same thing in the near future... Any
> progress? Keep us updated!
> Sorry I'm not of any help... What you could try: how do other GIS packages
> interact with your updatable view?
>
> Rob
>
> 2009/10/24 Ricardo Filipe Soares Garcia da <ricardo.garcia.silva at gmail.com>
>>
>> Hello list
>> I am using Qgis 1.3.0 compiled from the release tarball on Kubuntu 9.04.
>>
>> I am trying to create an updateable postgis view that will be updated
>> through Qgis.
>>
>> I have a postgis DB with spatial and non-spatial tables. I'm using a
>> view to abstract the relational connections between several tables and
>> a spatial table and present the user (me) with a flat-file-like type
>> of visualization through Qgis, so that I can see the real values of my
>> spatial data instead of a bunch of foreign keys. This visualization is
>> working fine, I have created the postgis view and can use it inside
>> Qgis.
>>
>> Now I'd like to be able to use Qgis to insert and update my view and
>> have postgresql do the real inserting and updating to my tables in the
>> background. For this purpose I am creating some postgresql rules as in
>> shown in [1] and [2]. So far I have succeeded in creating the UPDATE
>> rule, which is working really nice and I think I have successfully
>> created the INSERT rule as well, but I'm unable to test it due to Qgis
>> crashing.
>>
>> My problem lies with the creation of new geometries.
>> So far Qgis is crashing with the 'Segmentation fault' message when I
>> try to create a new polygon on the view layer:
>> To replicate the crash:
>>    1 - load postgis layer (this layer is a postgis view, definded
>> with SQL code in [3]) in Qgis
>>    2 - toggle the edit mode to 'on'
>>    3 - select the 'capture polygon' tool
>>    4 - click anywhere on the map canvas
>>    5 - ugly crash (segmentation fault reported on the console)
>>
>> Is it not possible to draw a new feature on a view layer? can someone
>> replicate this behaviour? If not, it really should because the insert
>> rule on postgres's side will (hopefully and most likely) accept that.
>> Please note than I can update an already existing feature (for example
>> moving some vertices around) and it works ok.
>>
>> Thanks in advance
>>
>> [1] -
>> http://www.postgresonline.com/journal/index.php?/archives/11-Database-Abstraction-with-Updateable-Views.html
>> [2] - http://www.postgresql.org/docs/8.1/interactive/rules-update.html
>> [3] - SQL code follows:
>>
>> CREATE OR REPLACE VIEW salasp1 AS
>>        SELECT s.sa_gid, s.the_geom,
>>                e.sigla AS edificio, p.numero AS piso,
>>                s.nome AS sala, t.tipo, f.funcionalidade,
>>                d.sigla AS sigla_dep_servico, d.nome AS dep_servico,
>>                s.descricao, s.lugares, s.tomadas, s.telefones
>>        FROM sala s, tipo t, funcionalidade f, piso p, edificio e,
>> deptoservico d
>>        WHERE p.numero=1 AND p.pi_gid=s.pi_gid
>>                AND s.ti_id=t.ti_id AND s.fu_id=f.fu_id
>>                AND e.sigla='C8' AND d.dep_id=s.depserv_id;
>>
>>
>> --
>> ___________________________ ___ __
>> Ricardo Garcia Silva
>> _______________________________________________
>> Qgis-user mailing list
>> Qgis-user at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/qgis-user
>
>



-- 
___________________________ ___ __
Ricardo Garcia Silva