[Qgis-user] Spatialite VIEW in QGIS question

[Bernd Vogelgesang]

Am 19.02.2014 16:55, schrieb Alex Mandel:
> On 02/18/2014 12:29 PM, Bernd Vogelgesang wrote:
>> Hi folks,
>>
>> I'm quite desperate, cause I do not seem to understand what I'm doing
>> wrong, or if it's just not possible to do.
>>
>> I have a polygon layer in my spatialite database and a normal table with
>> bird observations. There are many observation entries for each item in
>> the polygons.
>> They share the simple field "id".
>>
>> I created dozens of view, following strictly
>> http://www.gaia-gis.it/spatialite-3.0.0-BETA/spatialite-cookbook/html/sp-view.html
>> (and i REALLY can't find any other tutorials).
>>
>> When i query "SELECT * FROM "test17"" in Spatialite GUI, it shows all
>> the lines with different observation entries for each polygon id, when i
>> load the VIEW in QGIS, it doesn't but duplicates the first matching
>> observation for one polygon over and over.
>>
>> The idea is to quickly identify all observations when selecting a
>> polygon, and then go to the attribute table to see which species are there.
>>
>> Is it possible to create a one-to-many spatial VIEW with Spatialite GUI  ?
>> if yes
>> Whats the trick?
>> if no
>> Is QGIS just not able to show the views table correctly?
>> if no
>> Whats the trick?
>>
>> Wasted many days on that now, and time is running away.
>>
>> Please, someone, heeeeelp
>>
>> Bernd
>>
>>

> I usually cheat, and in making my View I do a left join to the attribute
> table with the geometries. It ends up duplicating the geometries for
> each match which can be inefficient on a large dataset but works
> perfectly reasonable most of the time.
>
> Then the regular info and select tools return multiple records.
Thank you Alex for your answer.

I think this combination was the only one I haven't tried yet.

But ... the outcome is as depressing as all my other, or even worse. 
Instead of 37 features i now have 9725, and the attribute table has the 
same amount of entries instead of some 700.

When loading the attribute table, there are only ERROR in the fields, 
and it took some minutes till I was able to switch to "show only 
selected". And ... surprise surprise, it again showed just the entry of 
the first species in all of the rows instead of all the individual 
observations.

Guys, this is a very sad topic and I really can't understand how people 
can work with 1:n data even on the most basic level under these 
circumstances ...
Or doesn't anyone work with 1:n data? Well, the the world I'm living in 
is full of that ...

After nearly one week of trial and error, I am giving up now.

Cheers
Bernd

> I do see potential for a plugin that simply executes a filter on one
> table based on the selection in another table for a pre-defined
> relationship (maybe there is one already).
>
> Thanks,
> Alex
>
>