I agree with all of you about not reinventing the wheel and, yes, let's not fragment QGIS' capabilities on data querying/filtering/etc. My first idea was simply (but I'm not sure how much simple it is) to be able to perform aggregate queries like in WINDOW functions. In my job it's something I find very useful, and I would like not to have to export my layers to a PostGIS DB just to do it.
Some basic examples: - get the average area of some polygon features - get the relative dimension against some other feature's dimensions - etc. AFAIK these kind of queries cannot be run on Sqlite in one single shot. This is why I wasn't thinking to Sqlite (or SQL anyway) to implement it, but as an extension to expression engine, in a MapReduce pattern perspective... giovanni 2014-05-27 15:03 GMT+02:00 Régis Haubourg < regis.haubo...@eau-adour-garonne.fr>: > Hugo Mercier wrote > > Or > >> calculated fields in view can't be explicitly cast, so QGIS should have > >> to > >> guess data type based on a data scan (a major unadressed issue of > sqlite) > > > > Hmmm I wasn't aware of this limitation in SQLITE views :( > > Yes, SQLITE does dynamic typing, so user or provider has to scan values to > guess the right type. > Here is a sqlite topic on that [0] > And here my initial post in qgis list [1] > > [0] > > http://sqlite.1065341.n5.nabble.com/Computed-columns-in-VIEWs-return-NULL-but-should-be-able-to-be-typed-Any-ideas-td56769.html#a56770 > > [1] > > http://osgeo-org.1560.x6.nabble.com/Spatialite-can-t-type-fields-of-a-view-td5058436.html > > > > > -- > View this message in context: > http://osgeo-org.1560.x6.nabble.com/have-aggregate-window-expressions-ever-been-discussed-tp5142215p5142714.html > Sent from the Quantum GIS - Developer mailing list archive at Nabble.com. > _______________________________________________ > Qgis-developer mailing list > Qgis-developer@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/qgis-developer > -- Giovanni Allegri http://about.me/giovanniallegri Twitter: https://twitter.com/_giohappy_ blog: http://blog.spaziogis.it GEO+ geomatica in Italia http://bit.ly/GEOplus
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