[Qgis-developer] 1:many relation enhancements

[Hugo Mercier]

Le 22/10/2014 08:39, Matthias Kuhn a écrit :
> Hi Régis
> 
> On 10/21/2014 09:44 PM, HAUBOURG wrote:
>> Hi Matthias,
>> Agregate functions could be provided by virtual table feature (qep is
>> coming I think), I suppose we should chose one common way for advanced
>> relationnal capabilities.
> 
> I agree that one common way is preferable, but actually this QEP itself
> is already duplicating functionality (of QgsExpression) and nobody was
> able yet to confirm that it is possible to optimize queries for
> execution on the database with sqlite virtual tables. Something that is
> a must from my point of view. I think it is a good initiative, but for
> the aforementioned reasons I am not yet completely convinced, that it's
> the one and only way.

Hi,

Since I'm the author of the mentioned QEP
(https://github.com/qgis/QGIS-Enhancement-Proposals/pull/5), I have to
answer :)

What functionalities of expressions do you think it duplicates ?

I don't see anything that prevents virtual layer queries from being
optimized server-side. It has to be taken into account during the
implementation of virtual layers, of course, but it is hard to exhibit
the precise way it will work now without having an almost complete
implementation.
Anyway, it will try to complete my proposal with some more concrete
material about that when I find time.